SURGICAL    ANATOMY 

OF    THE 

HEAD    AND    NECK 


D  E  A  V  E  R 


BY  THE  SAME  AUTHOR 


SURGICAL  ANATOMY.— A  Treatise  on  Human  Anatomy  in  its  Application  to  the 
Practice  of  Medicine  and  Sargery.  In  Three  Royal  Octavo  Volumes,  including  499 
Full-page  Plates.  Sold  by  Subscription  Only.  Full  Sheep  or  Half  Morocco, 
$30.00 ;    Half  Russia,  $33.00  net. 

GENERAL  ARRANGEMENT  OP  CONTENTS 

Volume  I. — Upper  Extremitj' — Back  of  Neck — Shoukler — Tniiik — Cranium — Soalp — Face. 

Volume   II. — Xeck — ]\Iouth — Plianiix — Larynx — Nose— Orliit — Eyel)aU — Organ    of   Hearing — 
Brain — JIale  Perineum — Female  Perineum. 

Volume  III. — Abdominal  Wall — Abdominal  Cavitj' — Pelvic  Cavity — Che-str — Lower  Extremity. 


APPENDICITIS. — Its  History,  Anatomy,  Etiology,  Pathology,  Symptoms,  Diagnosis, 
Prognosis,  Treatment,  Complications  and  Sequelse,  with  five  Colored  and  many  other 
Full-page  Plates.     Third  Edition.     Cloth,  $5.00. 


ENLARGEMENT  OF  THE  PROSTATE.— Its  History,  Anatomy,  Pathology,  Causes, 
Symptoms  Diagnosis,  Treatment,  and  Technique  of  Operations.  Illustrated.  Oc- 
tavo. In  Press. 


SURGICAL  ANATOMY 


OF  THE 


HEAD    AND    NECK 


JOHX    B.    DEAVER,    M.D 

SURGEOS-IS-CIIIEF  TO  THE  GKUMAN    IMSIMTAI.,   PHILADELPHIA 


jLH.STRATED  by  177  PLATES  NEARLY  ALL  DRAWN  FllOM  ORIGINAL  DISSECTIONS 


NECK;     MOUTH;     PHARYNX;    LARYNX;    NOSE;    ORBIT;    EYEBALL; 

ORGAN  OF  HEARING;    BRAIN;    BACK  OF  NECK; 

CRANIUM;    SCALP;    FACE. 


PHILADELPHIA 

P.  BLAKISTON'S    SON    &    CO. 

1 0  1  J    WALNUT    STREET 

1  904 


Copyright,  1904,  by  P.  Blakiston's  Son  k  Co. 


WM.   F.   FELL    CO. 

ELECTROTyPenS   AND    PRINTERS 

1320-34    SAN^OM    STREET 

PHILADELPHIA 


700 


PUBLISHERS'   NOTE. 


This  volume  has  been  made  up  from  those  sections  of  Dr.  Deaver's  complete 
work  on  "Surgical  Anatomy"  which  treat  specially  of  the  regions  which  arc  of 
greatest  interest  to  tiiose  practitioners  who  confine  their  work  to  Diseases  of  tlie 
Eye,  Ear,  Nose,  Mouth,  Throat,  and  Nervous  System,  and  [irovides  this  class  of 
specialists  with  an  absolutely  unique  book,  useful,  practical,  new. 

The  illustrations  which  were  prepared  to  exemplify  the  text  have  l)een  drawn 
directly  from  dissections  made  for  the  purpose.  They  are  accurate,  artistic,  real- 
istic, and  are  reproduced  in  accordance  with  the  liighest  standards  of  tyiiography. 

The  text  is  clear,  succinct  and  systematically  arranged.  It  sets  forth  the  prin- 
ciples of  anatomy  as  applied  to  medicine  and  surgery  and  describes  with  thorough- 
ness the  anatomic  conditions  fundamental  to  the  various  surgical  operations. 


G350;:.l 


CONTENTS 


PACK 

THE  NECK 17 

SuRFACE  Anatomy  of  the  Neck, 17 

Dissection  of  the  Neck, 2G 

Triangles  of  Neck, 54 

Cervical  Plexus  of  Nei-ves, G5 

Extrinsic  JIuseles  of  Toiijiue, 108 

Tiiyroid  Gland, 1212 

Axillary  or  Brachial  Plcxn.s,      148 

Bursse  of  Neck,      156 

Lyiiiiihalic  Glands  of  Neck, 159 

LiG.ATiON  OF  Arteries  of  Head  and  Neck, IGO 

Operations  Upon  Nerves  of  Head  a.vd  Neck, 196 

THE  MOUTH .  209 

The  Tongue : 216 

Muscles  of  the  Tongue, 219 

The  Tonsils 224 

THE  PHARYNX, 227 

Kel.\tio\s  of  the  Pharynx, 237 

Veins  of  the  Pharynx 238 

Lymphatic  Vessels  of  the  Pharynx, 238 

THE  SOFT  PALATE, 238 

THE  LARYNX, 247 

Veins  of  the  Larynx 205 

Lymph.\tic  A'e.ssels  of  the  Larynx 265 

The  Vocal  Cords,     266 

The  Cartilages  of  the  Larynx, 270 

THE  NOSE 284 

The  Nasal  Bones 286 

Cartilages  of  the  Nose 286 

THE  FRONTAL  SLXUSES, 308 

THE  ANTRUM  OF  HIGHMORE, 312 

THE  ETHMOID  SINUSES, 315 

THE  SPHENOID  SINUSES, 315 

THE  ORBIT 316 

Dissection  of  the  Orbit, 317 

MrscLES  OF  THE  Orbit, 328 

THE  LACRYMAL  APPARATUS 351 

vii 


viii  CONTENTS. 


PAGE 


THE  EYEBALL,    . - 357 

THE  ORGAN  OF  HEAEING, 399 

The  External  Ear, 399 

The  Middle  Ear, 407 

The  Internal  Ear, 431 

MEMBRANES  AND  VESSELS  OF  THE  BRAIN 438 

THE  ARTERIES  OF  THE  BRAIN. 445 

THE  VEINS  OF  THE  BRAIN, 4.')4 

THE  BRAIN, 455 

Surface  Markings  op  the  Brain,      455 

The  Origins  of  the  Cranial  Nerves,     4til 

The  Cerebrum, 4(17 

Surfiice  Jlai-kings, 467 

Cranio-Cerebral  Topograpliy, 499 

Motor  Centers, 500 

Interior  of  Cerebrum, 512 

The  Lateral  Veiitrieles, 518 

THE  PONS  VAROLII, 549 

THE  MEDULLA  OBLONGATA,     553 

THE  CEREBELLUM, 558 

SECTIONS  OF  THE  BRAIN, 507 

JOINTS  OF  THE  HEAD  AND  NECK, 573 

DISLOCATIONS  OF  THE  BONES  OF  THE  VAULT  AND  BASE  OP  SKULL,   ....  579 

DISLOCATION  OF  THE  LOWER  JAW, 579 

EXCISION  OF  THE  UPPER  JAW 579 

EXCISION  OF  THE  LOWER  JAW 583 

FRACTURES  OF  THE  SKULL,      584 

SURFACE  ANATOMY  OF  THE  CRANIUM, 587 

SURFACE  ANATOMY  OF  THE  FACE, 592 

SCALP 601 

FACE,     625 

PrEiiVGO-jiAxii.i.AKv  Hkgion 676 

TIIK  MEMBRANES  AND  VESSELS  OF  THE  BRAIN 704 

Intra  cranial  Course  and  BIode  of  Exit  op  the  Cranial  Nerves 727 

INDEX,     .   .     737 


LIST  OF  ILLUSTRATIONS. 


PLATE  PAGE 

I.  Lines  of  Incision  fur  EsjMisure  of  Arteii(^t4  and  Nerves  of  Neck, 20 

II.   Surface  Anatomy  of  Neck,  and  Lines  of  Incision  in  Laryngotomy,  High  Tra- 

cheutoniy  anil  Low  Traelieotoiuy, 21 

III.  lacisions  for  Dissection  of  Neck,  auclLines  for  Vessels  and  Nerves  of  Neck,     .  27 

IV.  Platysma  Jlyoides  Muscle, 30 

V.   Superficial  Layer  of  Deep  Fascia,  Supei-ficial  Veins,  and  Nerves  of  Neck,  ...  34 

VI.   Veins  of  Scalp,  Face,  and  Neck, 35 

VII.   Section  of  Neck  at  Sixth  Cervical  Vertebra, 39 

VIII.  Diagram  of  Deep  Cervical  Fascia, 41 

IX.  CeiTieal  Plexus, 44 

X.  Superficial  Structures  of  Neck,      50 

XI.  Superficial  Structures  of  Neck 51 

XII.  Diagram  of  Triangles  of  Neck,      55 

XIII.  Incisions  for  Di.ssection  and  Lines  for  Arteries,  Veins,  and  Nerves  of  Neck,    .    .  07 

XIV.  Vessels  and  Nerves  of  Neck 70 

XV.  Vessels  and  Nefves  of  Neck,      71 

XVI.  Deep  Structures  of  Neck — Carotid  Arteries  and  Piieuiuogastric  Nerve,    ....  78 

XVII.   Sympathetic  Nerve  and  Laryngeal  Nerves, 79 

XVIII.  Diagram  of  Subclavian  and  Carotid  Arteries  and  Tbeir  Branches, 87 

XIX.   Veins  of  Head  and  Neck 89 

XX.   Superficial  Stiiictures  of  Neck,      100 

XXI.  Superficial  Structures  of  Neck, 101 

XXII.  Arteries  of  Tongue  and  Tonsil,      105 

XXIII.  Extrin.sic  Muscles  of  Tongue, 109 

XXIV.  Supei-ficial  Structures  Near  Median  Line  of  Neck, 117 

XX^^  Thyroid  Body 123 

XXA'I.  Thoracic  Duet, 129 

XX^'II.   Collateral  Circulation  after  Ligation  of  Subclavian  Artery,      133 

XX^'III.   Vertebral  Artery  in  Transverse  Processes, 137 

XXIX.  Vessels  of  Neck 140 

XXX.  Vessels  of  Neck, 141 

XXXI.  Axillary  or  Brachial  Plexus  pf  Nerves, 149 

XXXII.    Prevertebraniu.-icles ],52 

XXXIII.  Lymiihatic  Glands  and  Lymi)hatic  Vessels  of  Neck, 157 

XXXIV.  Lines  of  Inei.sion  for  Operations  on  Nerves  and  Arteries  of  Head  and  Neck,  .    .  161 
XXXV.   Expo.sure  of  ImKinjinate  Artery, 104 

XXX\'I.   Expo.sure  of  Third  Portion  of  Subclavian  Artery,      107 

XXX\'II.  Diagram  of  Collateral  Circulation  after  Ligation  of  Subclavian  and    Common 

Carotid  Arteries, 171 

XXXVIII.    Expo.sure  of  Vertebral  Arteiy  and  Inferior  Thyroid  at   Origin — Left   Side  of 

Neck .'^ 174 

XXXIX.   Ligation  of  First  and  Seconil   Portions  of  Lingual  Artery;  Superior  Thyroid 

Artery;  Inferior  Thyroid  Artery, 177 

ix 


LIST  OF  ILLUSTRATIONS. 


PLATE 

XL. 


XLI. 


XLII. 

XLIII. 

XLIY. 

XLV. 

XLVI. 

XLVII. 

XLAIII. 

XLIX. 

L. 

LI. 

LII. 

LIIL 

LIV. 

LV. 

LVL 

LVIL 

LAIII. 

LIX. 

LX. 

LXL 

LXIT. 

LXIII. 

LXIV. 

LXV. 

LXVL 

LXV  1 1. 

LXVIIL 

LXIX. 

LXX. 

LXXI. 

LXXII. 

LXXIIL 

LXX  TV. 

LXXV. 

lA'XVI. 

LXXVIL 

LXXVIIL 

LXXTX. 

LXXX. 

LXXXL 

lAXXH. 

LXXXin. 

LXXXIV. 

LXXXV. 

LXXX  V  I. 

Lxxxvn. 

LXXX  VII  [. 

LXXXLX. 

XC. 


P.IGE 

Exposure  of  Inferior  Dental  Nerve  ;   Facial  Artery  ;    Spinal  Accessory  Nerve 
and  Superficial  Brauches  of  Cervical  Plexus;  anrl  Cnuinion  Carotiil  Artery 

in  Superior  Carotid  Triangle,      182 

Exposure  of  External  Carotid  and  Internal  Carotid,  and  of  the  Superior  Thyroiil, 
Lingual,  Facial,  and   Occipital  Arteries  at   Tlicir   Oiigin,  and   Exposure  i.f 

Common  Carotid  in  the  Inferior  Carotid  Triangle, ]S3 

Exposure  of  Occipital  Artery  for  Ligation, ]'.)2 

Exposure  of  Auriculo-temporal  Nerve  and  Temporal  Artery,     193 

Exposure  of  Supraorbital  Artery  and  Nerve,     197 

Exposure  of  Lingual  Artery,      202 

Exposure  of  Facial  Nerve,      203 

Exposure  of  Bracliial  Plexus  of  Nerves, 208 

Vertical  Section  of  Mouth,  Pharynx,  Larynx,  and  Nose, 212 

Superior  Aperture  of  Larynx  and  Dorsum  of  Tongue, 218 

Transverse  Section  of  One-half  of  Tongue, 221 

Constrictor  Muscles  of  Pharynx, 229 

Pharyngeal  Tonsil  and  Bursa, 233 

Interior  of  Pharynx, 23G 

Anterior  View  of  Jloutli 239 

Muscles  of  Soft  Palate — Anterior  Mew, 242 

Muscles  of  Soft  Palate, 243 

Superior  Aperture  of  Larynx, 250 

Larynx  and  Crico-thyroid  Sluscle 2.51 

Anterior  View  of  Larynx,  Including  the  Cricothyroid  Membranes, 254 

Jlusoles  of  Larynx — Posterior  View, 258 

JMuscles  of  Larynx — Lateral  ^'iew, 259 

Nerves  and  Arteries  of  Larynx, 263 

Lateral  View  of  Interior  of  Larynx, 267 

Cartilages  of  Larynx, 27 1 

Surface  IMarks  of  Neck  and  Lines  of  Incision  f  )r  Laryngotomy  and  Tracheotomy,  278 

Operation  of  Laryngotomy  and  High  and  Low  Tracheotomy, 279 

Lateral  Cartilages  of  tlie  Nose,      287 

Cartilages  at  Base  of  Nose 290 

Nasal  Septum, 291 

IMeatuses  of  Nose  and  Turbinated  Bones— Lateral  View, ...  296 

Orifices  of  Accessory  Air-chambers  of  Nose,      298 

Olfactory  Nerves,      303 

Anterior  View  of  Nasal  Fosspb,      306 

I'osterior  View  of  Nasal  Fossre, 309 

Oridces  of  Nasal  Duct  and  Accessory  Air-chambers  of  Niise, 314 

Orbital  Fascia  and  Capsule  of  Tenon — Sagittal  Section 320 

Orbital  Fascia  and  Capsule  of  Tenon — Transverse  Section,      321 

Nerves  and  Muscles  of  Orbit, 326 

Muscles  of  Oibit,      330 

Arteries  and  Veins  of  Orbit, 334 

Nerves  of  Orbit 339 

Section  of  Cavernous  Sinus — Structures  Traversing  Spheuoi.l  Fissure,     ....  343 

Tensor  Tarsi  and  Corrugator  Supei'cilii  Muscles, 346 

Lacrymal  Ajuiaratus 350 

Sagittal  Section  of  Ui)i)er  Eyelid, 353 

[Meibomian  (Jlands  and  Laerymal  A])paratus,      355- 

Meridional  Sei'tion  of  Eye, 360 

Meridional  Section  of  Ciliary  Region  of  Eyeball, 365 

External  and  Middle  Coats  of  Eyeball 369 

Ciliary  Region  of  Eyeball  (from  Lion's  Eye  in  Museum  of  Univ.  of  Pemia.),    .  372 


LIST  OF  ILLUSTRATIONS.  xi 

PI.ATK  P.4GK 

XCr.  Ciliary  Ntrves 370 

X("ll.  Ciliary  Aiteiios, 377 

XCIII.  Rotiua  of  Posterior  Oiio-lialf  of  Eight  Eyeball, 381 

XCn'.  Blood-vessels  of  I'lyeball  (after  Leber) 384 

XCV.  Lens,  Iris,  ami  Ciliary  Hody  at  Rest;  the  Same  Structures  lluring  Aecommo- 

dation.     Kniniitroiiic  Eye,      388 

XCVL  Myopic  Eye  ;  i^lyopie  Eye  with  Concave  Lens  ;  Hyperoinc  Eye  ;  Ilyperopic  Eye 

with  Convex  Lens, 389 

XC\'H.  Annual  Posterior  Synechia, 304 

XCVIIL  Pinna  of  Ear,     .    ." 398 

XCIX.  Litrinsic  Muscles  of  Piinia 401 

C.  External  and  Midille  Ear 405 

CL  Anterior  Vii'W  of  Right  Tympanum, 409 

CIL  Membrana  Tympani  and  Its  Inclination, 413 

cm.  External  View  of  ^Membrana  Tympani  ol'  Lel't  Ear,    .    .    .    / 418 

CIV.  Internal  View  of  Right  Tynjpanum, 422 

CV.  External  View  of  Bony  Labyrinth  and  Semicircular  Canals, 427 

CVI.  Interior  of  Osseous  Labyrinth  of  Left  Internal  Ivir, 430 

CWl.  Interior  of  Osseous  Portion  of  Cochlea, 434 

CVIII.  Section  of  Osseous  Portimi  of  Cochlea, 435 

CIX.  Diagram  of  Membranuus  Labyrinth, 439 

ex.  Circle  of  Willis  and  Arteries  of  Brain 444 

CXI.  Middle  Ccreljral  Artery 447 

CXJI.  Arteries  at  Base  of  Brain, 452 

CXIII.  Base  of  Brain  and  Superfici.d  Oiigin  of  Cranial  Nerves,     458 

CXIV.  Diagram  of  Optic  Tr.icts, 463 

CXV.  Island  of  Rcil, 471 

CXA'I.  Diagram  of  Lateral  Surface  of  Cerebrum, 474 

CXVII.  External  Surface  of  Cerelirum,      477 

CXVIII.  Superior  Surface  of  Cerebrum, .  480 

CXIX.  Inferior  Surface  of  Frontal  Lobe,      483 

CXX.  Median  and  Ini'erior  Surfaces  of  Cerebrum 488 

CXXI.  Inferior  Surface  of  Occi])ital  and  Temporal  Lobes, 494 

CXXII.  Median  and  Inferior  Surfaces  of  Cerebrum, 497 

CXXIII.  Motor  and  Sensory  Areas  of  Cerebrum  (after  Ferrier), 501 

CXXI\^.  Lines  for  Fissures,  Lower  Level  of  Cerebrum 506 

CXXA'.  Corpus  Callosum  and  ILjrizontal  Section  of  Cerebrum, 513 

CXX^'I.  Internal  Surface  of  Cerebrum  and  Section  of  Ventricles  of  Brain, 516 

CXXA'II.  Bodies,  Anterior  Cornua,  and  Posterior  Cornua  of  Lateral  Ventricles,      ....  519 

CXX\'III.  Fornix  and  Lateral  ^^■ntricles.  and  Descending  Cornu  of  Left  Lateral  Ventricle,  523 

CXXrX.  Diagram  of  the  Ventiiclcs — Sujierior  View, 528 

CXXX.  Diagram  of  the  ^\■ntricles— Lateral  View, 529 

CXXXI.  Velum  Interpositum  and  Choroid  Plexus, 533 

CXXXII.  Ventricles  and  Nuclei  of  Brain, 536 

CXXXIII.  Lateral  View  of  Corpora  Quadrigemina,  P(]ns,  and  Medulla,      539 

CXXXIV.  Third  and  Fourth  Ventricles  and  CorjxiiM  Qnadi'igcmina 542 

CXX XV.  Transverse  Section  of  Cerebrum, 546 

CXX.WI.  Pons,  Medulla,  and  Superficial  Origins  of  Cranial  Nerves 5.52 

CXXX \' II.  Third  and  Fourth  ^'eutricles  and  Corpora  Quadrigemina, 556 

CXXX\"III.  Inferior  and  Superior  Surfaces  of  Cerebellum 560 

CXXX IX.  Coronal  Section  of  Cerebrum, 564 

CXL.  Coronal  Section  of  Ccrebrnni,  Anterior  to  Optic  Chia.sm 565 

CXLI.  Coronal  Section  of  Cerebrum  Through  Corpora  Albicantia  and  Middle  Commissure,  569 

CXLII.  Parietal  .and  Transverse  Occipital  Fi.ssures.    Lines  in  which  the  Bone  is  Divided 

iu  Excision  of  the  Ui)per  Jaw, 572 


xii  LIST  OF  ILLUSTRATIONS. 

PLATE  PAGE 

CXLIII.  Teruporo-masillaiy  Articulation — External  View, 576 

UXLIV.  Temporo-maxillary  Articulation — Internal  "^'iew,      577 

CXLV.  Fractures  of  Lower  Jaw, 581 

CXLVI.  Cranial  Landmarks  and  Lines  of  Cerebral  Fissures, 589 

CXLVII.   Incisions  for  Dissection, 597 

CXLVIII.  Layers  of  Scalp, 599 

Cirsoid  Aneur.vsm, 599 

CXLIX.  Superficial  Fascia  of  Scalp 603 

CL.  Arteries  of  Scalp  and  Face, 608 

CLI.   Nerves  of  Scalp  and  Facial  Nerve,      609 

CLII.  Arteries,  NeiTes,  and  Muscles  of  Scalp  and  Face, .  613 

CLIII.  Temporal  Fascia  and  Nerves  of  Face, 620 

CLIV.  Temiioral  JIuscle, 621 

CLV.   Incisions  for  Dissection  and  Lines  for  Vessels  and  Nerves  of  Face, 623 

CL'\'I.   Bluscles  of  Face  and  Scalp, 627 

CLVII.  Tensor  Tarsi  and  Corrugator  Supereilii  Muscles, 632 

CLVIII.  Arteries  of  Scalp  and  Face, 640 

CLIX.  Arteries,  Nerves,  and  ^Muscles  of  Scalp  and  Face, 641 

CLX.   Veins  of  Scalp,  Face,  and  Neck 645 

CLXI.  Palpebral  Fissure  and  Eyeball— Eyelids  Everted, 649 

CLXII.   Lacrymal  Apparatus  and  Meibomian  Glands, 653 

CLXIIL  Pinna, 661 

CLXIV.   Intrinsic  Muscles  of  Pinna 663 

CLXV.   Nerves  of  Scalp  and  Facial  Nerve 667 

CLXA'I.   Operation  for  Exjiosure  of  Facial  Nerve, 672 

CLX^'II.   Temporal  Fascia  and  Nerves  of  Face 673 

CLXA'III.   Pterygoid  J^Inscles  and   Internal  Maxillary  Artery 678 

CLXIX.  Internal  ^Maxillary  Artery  and  Brandies, 682 

CLXX.  Inferior  Maxillary  Nerve; 686 

CLXXI.   Olfactory  Nerves  and  Internal  View  of  the  Spliono-palatine  and  Otic  Ganglia,     .    .  690 

CLXXII.   Superior  and  Inferiiir  3Iaxillary  Nerves, 695 

CLXXIII.   Diiiloic  Veins 705 

CLXXIV.  Dura  Jlater,  Arachnoid,  and  Meningeal  Vessels,      709 

CLXXV.  Sinuses  and  Processes  of  Dura  Mater, 714 

CLXXVL  Sinuses  and  Cranial  Nerves 715 

CLXXVII.  Lines  for  Sinuses, 721 


SURGICAL   ANATOMY 

OK   TIIK 

HEAD  AND  NECK. 


Dlii;^ECTluy    OF   THE  NECK. 
SURFACE  ANATOMY. 

The  surface  anatomy  of  the  region  of  the  neck  should  be  considered  in  re- 
gard to  its  superficial  veins  and  nerves,  the  upper  portion  of  the  respiratory  tract, 
the  prominent  muscles,  the  ])uInionary  apices,  the  sterno-cluvicular  joints,  and  the 
hirge  vessels.  The  skin  of  the  front  of  the  neck  may  lie  eitlier  in  hui-jzontal  or 
vertical  folds,  the  former  being  more  common,  and  always  seen  in  infants.  In 
stout  persons  the  deposition  of  fat  in  the  subcutaneous  tissues  makes  these  folds 
very  prominent,  producing  the  cimdition  known  as  "  double  chin."  Vertical 
folds  occur  in  the  aged,  especially  in  those  who  have  lost  much  adipose  tissue, 
in  consequence  of  which  the  old  and  inela.stic  skin  can  no  longer  adapt  itself 
The  anterior  and  most  prominent  ridges  of  the  surface  of  the  neck  an'  lUie  to  the 
anterior  liorder  of  the  platysma  myoides  muscles. 

Length  of  the  neck. — The  variabilit}-  which  exists  in  the  length  of  the  necks 
of  dilferent  persons  is  due,  as  Merkel  points  out,  to  three  factors :  First,  to  the 
position  of  the  shoulder  girdle  ;  second,  to  the  contour  of  the  border  of  the  trape- 
zius muscle  ;  third,  to  the  thickness  of  the  neck.  The  superior  thoracic  aperture 
is  oblicjue  from  behind  forward  and  downward  ;  in  some  persons  this  nbli(juity  is 
greater  than  in  others,  so  that  the  supra-sternal  notch  may  be  on  a  level  with  the 
third  thoracic  vertebra  ;  this  will  consequently  cause  the  inner  end  of  the  clavicle 
to  lie  lower,  and  the  neck  will  appear  longer.  When  the  border  of  the  trajwzius 
muscle  slopes  graduaUy  toward  the  shoulder  instead  of  curving  I'ather  abruptly 
out u aid,  the  neck  will  appear  longer ;  a  thin  neck  presents  a  longer  appearance 
tlian  a  thick  and  muscular  one. 

The  length  of  the  cervical  jiortion  of  the  spinal  column  does  not  vary  much 
in  different  persons. 

The   sterno-cleido-mastoid  muscle,  because   of  its   prominence   throughout 
its   course,  is   the   great    landmark    of  the    neck,  and    extends  from  the  sterno- 
S-2  17 


18  SURGICAL  ANATOMY. 

clavicular  junction  to  behind  the  eai'.  An_v  movement  of  the  head  which  draws 
the  ear  downward  and  forward  renders  the  muscle  prominent.  It  divides  the 
side  of  the  neck  into  the  anterior  and  the  posterior  triangle.  In  subcutaneous 
section  of  the  lower  attachments  of  this  muscle  it  must  not  be  forgotten  that 
the  fossa  supraclavicularis  minor,  the  triangular  interval  between  the  sternal  and 
clavicular  origins,  marks  the  position  of  the  common  carotid  artery  and  internal 
jugular  vein. 

The  supra-sternal  fossa,  termed  "fonticulus  gtdturis"  by  the  old  writers,  lies 
betM'een  the  sternal  origins  of  the  two  sterno-mastoid  muscles.  In  Iwautiful 
necks  it  is,  of  course,  filled  with  fat,  but  even  then  the  rounded  contour  of  the 
sternal  attachment  of  this  muscle  is  evident,  though  graceful  withal.  "When  the 
finger  is  deeply  insinuated  into  the  supra-sternal  notch,  the  pulsations  of  the 
innominate  artery  can  often  be  felt ;  those  of  a  dilated  aortic  arch  may  also  be 
perceived.  Retraction  of  the  tissues  in  the  supra-sternal  notch  during  inspiration 
is  often  seen  in  marked  dyspnea,  as  in  larj'ngeal  obstruction. 

The  sterno-clavicular  joint  may  be  readily  identified  at  the  side  of  the  supra- 
sternal notch — in  stout  persons  by  movement,  and  bj'  sight  alone  in  thin  individ- 
uals. Its  upper  border  marks  the  origin  of  the  innominate  vein  upon  both  sides, 
behind  which,  on  the  left  side,  lies  the  common  carotid  artery,  and  on  the  right 
side,  the  bifurcation  of  the  innominate  artery ;  still  farther  back  is  the  apex 
of  the  lung.  The  innominate  arterj'  is  relatively  higher  in  children  than  in 
adults. 

The  apex  of  the  lung  extends  from  one  to  two  inches  above  the  clavicle,  and 
higher  in  very  long  necks ;  it  is  also  higher  in  women  than  in  men.  It  is  covered 
l)y  part  of  the  scalenus  anticus,  sterno-thyroid,  and  sterno-cleido-mastoid  muscles, 
and  to  the  inner  side  of  the  scalenus  anticus  muscle  it  is  crossed  transversely  by 
the  subclavian  vessels.  This  portion  of  the  lung  is  more  commonly  the  site  of 
tubercular  deposits,  ajid  should  be  examined  by  percussion  and  auscultation 
immediately  above  and  ])elow  the  inner  part  of  the  clavicle. 

The  supra-clavicular  fossa  is  the  depression  above  the  clavicle  lietween  the 
sterno-mastfiid  and  trapezius  muscles.  The  external  jugular  vein  terminates  here. 
It  is  well  defined  in  emaciation  due  to  wasting  diseases  and  in  oM  age.  It  marks 
the  place  where  the  vessels  and  nerves  pass  from  the  neck  into  the  axilla,  and  a 
knife  thrust  backward,  downward,  and  inward  through  this  depression  would 
injure  a  number  of  important  structures.  Tlie  transverse  processes  of  the  cervical 
vertebnc  may  be  felt  by  pres.sure  directed  inward  tln-ough  the  uj)}icr  part  df  the 
fossa.  Ill  Ihin  jiersons  Uie  jiostcrior  lielly  of  the  omd-liyoid  muscle  can  also  be 
felt  in  this  space,  just  above  and  i)arallel  to  the  clavicle..  During  inspiration  the 
tension  ]iroduced  by  the  omo-liyoid  muscle  on  the  deej)  cervical  fascia  is  jdainly 


PLATE  I, 


External  carotid  a.  First  portion  of  lingual  a. 


Inferior  dental  n 
Facial  n 


ainal  accessory  n 
anterior  to  sterno-mastoid  m 


Spinal  accessory  n.  posterior  to  sterno- 
mastoid  m.  and  superficial  branches  of 
cervical  plexus 


Facial  a. 

Second  portion  of  lingual  a. 


Superior  thyroid  a. 


Common  carotid  a.  in 
superior  carotid  triangle 


Common  carotid  a.  in 
inferior  carotid  triangle 


X 


\ 


3d  portion  of  subclavian  a 


nnommate  a. 


LINES  OF  INCISION  FOR  EXPOSURE  OF  ARTERIES  AND   NERVES, 

20 


PLATE  II. 


f^ 


Prominence  produced  by  sterno- 
mastoid  m. 


Common  line  of  incision  for 
laryngotomy.high  traciieotomy 
and  low  tracheotomy 


Ridge  over  clavicle 

Supraclavicular  fossa 


-Segment  of  line  locating 
incision  in  laryngotomy 

-Segment  of  line  locating 
incision  in    high  tracheotomy 


Segment  of  line  locating 
incision  in  low  tracheotomy 


Suprasternal  fossa 
Fossa  supraclavicularis  minor 


SURFACE  ANATOMY  OF  NECK,  AND  LINES  OF  INJISION  IN  LARYNGOTOMY,  HIGH  TRACHEOTOMY,  AND  LOW  TRACHEOTOMY. 

21 


SURFACE  AXATOMY  OF  THE  MCCK.  23 

discernible.  Holdon  likens  its  central  tendon  to  a  ruiliuK'nlary  cervical  rih,  its 
posterior  belly  to  a  digitation  of  the  serratus  niaj;uus  muscle,  and  its  anti-rior  belly 
to  a  sterno-hye)id  ninsele. 

The  subclavian  artery  extends  from  one-half  of  an  inch  to  an  inch  above  the 
clavicle,  in  the  supra-clavicular  fossa,  close  to  tlie  external  border  of  the  stt'rno- 
mastoid  nniscle,  where,  by  moderate  pressure  directed  downward,  backward,  and 
inward,  it  can  readily  be  compressed  against  the  first  rib  ;  pressure  directed  other- 
wise would  meet  no  bony  resistance,  and  bleeding  could  not  be  controlled. 

The  carotid  arteries  are  readily  found  in  the  neck  along  the  anterior  or  inner 
margin  of  the  sterno-niastoid  muscle,  being  covered  by  its  anterior  border,  particu- 
larly in  the  lower  part  of  the  neck.  The  common  carotid  artery  divides  opposite 
the  up}ier  border  of  the  thyroid  cartilage.  From  this  point  at  the  anterior  border 
of  the  sterno-mastoid  muscle,  a  line  drawn  to  the  lobe  of  the  ear  indicates  the 
course  of  the  external  carotid  artery.  The  position  of  tlu^  connnon  carotid  artery 
is  represented  by  a  line  drawn  from  the  sterno-clavicular  articulation  to  a  point 
midway  between  the  angle  of  the  lower  jaw  and  the  mastoid  process. 

The  external  jugular  vein  passes  down  the  neck  in  a  line  drawn  from  the 
angle  of  the  inferior  maxilla  to  the  middle  of  the  clavicU'.  By  compression  of  its 
lower  end  the  vein  may  be  made  to  stand  out  j)ronnncntly.  Occasionally  ajit(/iilo- 
cephalic  branch  passes  over  the  clavicle  from  the  cephalic  to  the  external  jugular 
vein.  The  anterior  jugular  vein  is  usually  found  near  the  anterior  margin  of  the 
sterno-mastoid  nmscle. 

The  hyoid  bone,  directly  behind  the  lower  border  of  the  chin  in  the  ordinary 
attitude  of  the  head,  may  be  felt  in  its  entirety  through  the  skin.  Tn  its  upper 
border  are  attached  the  base  of  the  tongue  and  the  geniodiyoid  and  inylo-hyoid 
muscles,  which  form  the  fiooi-  of  the  mouth.  Below  the  body  of  the  bone  are 
the  thyro-hyoid  space  and  membrane,  the  center  of  which  corresponds  to  the 
position  of  the  epiglottis.  The  greater  cornu  of  the  bone  is  the  landmark  which 
locates  the  origin  of  the  superior  thyroid,  lingual,  and  facial  arteries.  The  origin 
of  the  superior  thyroid  artery  is  just  below  the  level  of  the  greater  cornu  of  the 
hyoid  bone,  that  of  the  lingual  artery  is  opposite  to  the  greater  cornu,  and  that 
of  the  facial  artery  is  just  above. 

The  thjrroid  cartilage  forms  the  anterior  projection  in  the  neck  called 
"  Adam's  apple  "  ;  it  is  larger  in  men  than  in  women,  so  that  there  is  increased 
length  of  the  vocal  cords,  which  have,  therefore,  in  accoi'dance  with  a  well-estab- 
lished law  of  phy.sic.s,  a  lower  pitch,  thus  accounting  for  the  deeper  tones  of  the 
male.  The  entire  cartilage  is  subcutaneous,  its  borders' and  cornua  being  easily 
traced  by  the  finger.  The  lateral  lobes  of  the  thyroid  gland  can  be  indistinctly 
felt  upon  each  side  of  the  cartilage,  and  it  is  said  the  i)ulsations  of  the  superior 
thyroid  artery  may  readily  be  felt  at  the  tip  and  front  of  the  lateral  lobe;  this, 


24  SURGICAL  ANATOMY. 

however,  is  exceptional.  Below  this  cartilage  is  the  crico-thyroid  space,  which  is 
occupied  by  the  crico-thyroid  membrane.  It  is  through  this  membrane  that  laryn- 
gotomy  is  performed,  care  being  taken  to  hug  the  upper  Ijorder  of  the  cricoid 
cartilage,  so  that  the  incision  may  be  as  far  as  possible  from  the  vocal  cords  and 
the  crico-thyroid  arteries. 

The  vocal  cords  are  situated  slightly  below  a  point  midway  between  the  deep- 
est part  of  the  incisura  tl\yroidese  and  the  lower  border  of  the  thyroid  cartilage. 

The  cricoid  cartilage  is  always  prominent,  and  can  readily  be  discerned.  It 
lies  opposite  the  sixth  cervical  vertebra.  Its  lower  border  is  on  a  level  with  the 
commencement  and  narrowest  part  of  the  esophagus ;  for  this  reason  all  l)odies 
which  have  entered  the  pharynx  but  are  too  large  to  pass  through  the  gullet  will 
lodge  behind  the  cricoid  cartilage.  The  cricoid  cartilage  is  just  above  the  level  at 
which  the  omo-hyoid  muscle  and  the  inferior  thyroid  artery  cross  the  carotid 
sheath,  the  muscle  being  in  front  of  the  sheath  and  the  artery  liehind.  Slightly 
below  the  level  of  this  cartilage  and  beneath  the  anterior  border  of  the  sterno- 
mastoid  muscle  is  the  carotid  tubercle,  against  which  the  common  carotid  artery 
may  be  compressed.  This  is  the  anterior  tubercle  of  the  transverse  process  of  the 
sixth  cervical  vertebra. 

The  movements  of  the  larynx  are  frequently  overlooked.  The  larynx  rises 
during  deglutition,  in  singing  a  high  note,  and  in  expiration  ;  it  descends  in 
singing  low  notes,  in  inspiration,  after  deglutition,  and  during  retching  and 
vomiting.  AA'hen  tlie  larynx  is  moved  from  side  to  side,  a  grating  sensation,  due 
to  the  friction  of  the  superior  cornua  of  the  thyroid  cartilage  against  the  spinal 
column,  is  perceived.  The  larynx  is  pu.shed  forward  in  the  passage  of  masses 
through  the  lower  pliarynx.  The  sudden  upward  ru.*h  of  vomited  matter  jn-oduces 
suction  upon  tlie  larynx,  drawing  out  obstinately  adherent  false  membrane  and 
collections  of  glairy  mucus ;  this  is  one  reason  for  giving  children  emetics  in  croup. 

The  trachea  is  situated  immediately  below  the  cricoid  cartilage.  Ordinarily, 
not  more  than  one  and  one-half  inches  of  it  appear  above  the  sternum  ;  an  inch 
more,  however,  may  be  revealed  if  the  neck  be  in  extreme  exten,sion.  This 
usually  leaves  alwut  eight  rings  in  the  neck,  of  whic-li  the  second,  third,  and  inurtli 
are  covered  by  the  thyroid  istlunus.  The  front  of  the  trachea  may  lie  ime  and 
one-half  inches  deep  at  the  top  of  the  sternum,  owing  to  the  recession  of  the  lower 
cervical  and  upper  thoracic  vertebrpe.  Opening  of  the  tracliea  to  relieve  dyspnea 
is  beset  witli  many  difficulties  not  all  demonstrable  in  llie  i-adaver — the  .strong  and 
ra])id  alternate  muscular  C(intracti(ins.  the  heaving  larynx,  the  distended  ;ui1eri(ir 
jugular  veins,  the  flexed  neck,  the  swollen  thyrdid  isllnnns,  llie  ilistended  thyroid 
plexus  of  veins,  and,  fre(|uently,  a  middle  thyroid  artery.  .\ll  imasious  into  the 
trachea  should  be  in  the  me(lian  line,  where  fewer  iniporlanl  slrneUires  need  be 
severed,     ll   is  often  advisable  in    cases   t)f  dysjmea,    to    incise   the    erii-o-thyroid 


SURFACE  ANATOMY  OF  THE  NECK.  25 

membrane,  and,  if  necessary,  the  cricoid  cartilago  may  l)e  divided.  If  a  lnwcr 
operation  be  required,  it  siioidd  be  done  whi'n  the  jiatient  has  Ix'coine  (|uieleil 
after  rehef  of  the  dyspnea. 

The  back  of  the  neck  jjresents,  above,  the  external  occipital  protuberance  and 
the  superior  curved  ridges  of  the  occipital  bone ;  below,  the  spinous  i)rocess  of  the 
seventh  cervical  vertebra  (vertebra  jirominens)  and  the  ligamentum  nucha'-,  extend- 
ing lietween  the  protuberance  and  tlie  spine  of  the  seventh  cervical  ^•e^teb^a. 
For  an  inch  below  the  superior  curved  ridges  of  the  occipital  lione  tiic  Ibiii  cere- 
bellar fossie  of  the  occiput  are  not  more  than  one-half  of  an  inch  fnun  llic  surface  ; 
tlieir  walls  are  so  thin  at  times  that  they  may  easily  be  penetrated  witli  a  sharp 
knife.  About  an  inch  below  the  external  occipital  protuberance  a  sharp,  narrow 
instrument  could  be  pushed  forward,  either  above  or  below  the  posterior  areli  of 
the  atlas,  thus  severing  tlie  upper  end  of  the  spinal  cord  and  destroying  life. 
About  one  or  one  and  one-half  inches  on  each  side  of  the  external  occipital 
protuberance  the  occipital  artery  pierces  the  trapezius  muscle,  below  the  superior 
curved  ridge,  and  passes  over  the  occiput  to  the  vertex  ;  it  is  accompanied  by 
the  great  occipital  nerve.  The  outer  margin  of  the  trapezius  muscle  merges 
with  the  shoulder  as  it  passes  to  it,  and  forms  the  graceful  outline  of  the  neck  so 
well  exhibited  in  some  of  the  lectures  of  noted  beauties.  Deep  pressure  in  llie 
median  line  near  the  occijiut  reveals  the  l:)ifid  spine  of  the  second  cervical 
vertebra.  The  spines  of  the  tliird,  fourth,  and  fifth  cervical  vertebi'je,  because 
of  their  shortness  and  recession,  are  not  readily  felt.  The  spine  of  the  sixth,  and 
more  especiall}'  of  the  seventh,  cervical  vertebra  may  easily  be  detected.  The  fifth 
cervical  spine  is  opposite  the  cricoid  cartilage  and  the  upper  end  of  tin^^  esophagus  ; 
that  of  the  seventh  is  behind  the  apex  of  the  lung,  which  is  higher  in  women. 

Congenital  cervical  fistulee. — A  lirief  resume  of  the  develojiment  of  the  neck 
is  here  introduced  in  order  to  explain  the  mode  of  occurrence  of  certain  interesting 
and  important  congenital  defects. 

The  antero-lateral  portion  of  the  neck  is  formed  largely  from  tlie  hrtnicJiidl  or 
lisceral  arches,  four  in  number  on  each  side,  connected  po.steriorly  witii  tlic  spinal 
column,  l)ut  not  at  first  uniting  anteriorly  with  one  ant)tber.  These  arches 
are  separated  from  one  another  by  the  branchial  clefts,  also  f()ur  in  nnnd)er  on 
each  side,  the  fourth  one  being  below  the  last  arch. 

The  first  or  mandibular  arch  is  concerned  in  the  formation  of  the  maxiihe  ; 
it  is  separated  from  the  second  arch  by  tlie  first  branchial  cleft,  Avhich  is  the  only 
cleft  remaining  in  the  adidt. 

Tlie  first  branchial  cleft  persists  as  the  external  auditory  meatus,  middle  ear, 
and  Eustachian  tul)e.  Irregularities  in  development  may  lead  to  the  formation  of 
fistulous  openings,  wliieh  are  usually  found  in  the  vicinity  of  the"  tragus  of  the  ear. 


26  SURGICAL  ANATOMY. 

The  lower  three  arches  are  concerned  in  the  formation  of  the  tissues  of  tlie 
neck. 

The  visceral  clefts  open  internally  into  the  pharynx  ;  no  coninuinication  of 
the  pharynx  with  the  exterior  ever  occurs,  for  a  delicate  membrane  divides  the 
cleft  into  an  inner  (pharyngeal   pouch)  and   an  outer  portion  (branchial  furrow). 

The  lower  three  clefts  normally  disappear,  certain  traces  found  in  the  pharynx 
and  larynx  alone  remaining. 

The  third  and  fourth  arches  are  small,  are  gradually  overlapped  by  the 
second  arch,  and  lie  in  a  depression  known  as  the  sinus  cervicalis.  It  is  through 
imperfect  closure  of  this  sinus  that  most  of  the  congenital  cervical  fistula  occur. 
These  are  narrow,  epithelium  lined  tracts,  opening  externally  near  the  anterior 
border  of  the  sterno-mastoid  muscle.  When  complete,  they  open  internally  into 
the  pharj'ux.  If  the  internal  portion  of  a  branchial  cleft  fail  to  become  obliter- 
ated, while  the  outer  portion  is  closed  as  normally,  a  pharyngeal  or  esophageal 
diverticulum  may  form.  Furthermore,  if  the  cleft  become  closed  externally  and 
internally  and  an  intermediate,  unobliterated  portion  persist,  the  epithelium  lining 
this  cavity  may  proliferate  and  undergo  various  changes,  and  thus  a  so-called 
branchial  cyst  result.  These  branchial  cysts  occur  in  the  submaxillary  and  supra- 
clavicular regions  and  at  the  borders  of  the  sterno-mastoid  muscle. 

Dissection. — The  neck  should  be  extended  and  made  prominent  by  placing  a 
block  beneath  the  shoulders.  An  incision  should  be  carried  from  the  symphysis 
of  the  lower  jaw  down  the  middle  line  of  the  neck,  to  the  middle  of  the  top  of  the 
sternum  ;  a  second  and  a  third  incision  should  be  made,  the  former  along  the 
clavicle  to  the  acromion  process,  the  latter  along  the  lower  border  of  the  lower  jaw 
to  the  angle  of  the  jaw,  thence  to  the  lobe  of  the  ear,  and  behind  the  ear  to  the 
transverse  incision  made  in  dissecting  the  scalp.  The  face  should  then  be  turned 
away  from  the  side  on  which  the  dissection  is  being  made,  and  retained  in  position 
with  hooks,  the  skin  being  raised  and  reflected  from  before  backward  to  beyond  the 
anterior  border  of  the  trapezius  muscle. 

The  skin  covering  the  side  of  the  neck  is  thin,  quite  elastic,  and  can  readily 
be  raised  into  folds,  which  always  contain  the  platysma  myoides  muscle ;  these 
conditions  favor  the  performance  of  plastic  operations.  In  these  respects  it  differs 
from  the  skin  over  the  nape  of  the  neck,  which  is  very  dense  and  adherent  and 
more  freely  supplied  with  nerves,  but  not  nearly  so  well  supplied  with  blood 
vessels.  Carbuncle  is  usually  seen  at  the  lower  part  of  the  back  of  the  neck  near 
the  median  line.  The  nape  of  the  neck  was  formerly  a  common  site  for  the  intro- 
duction of  setons  and  the  application  of  issues. 

The  superficial  fascia  now  exposed  is  a  very  thin  lamina  of  areolar  and  adi- 
pose tissue,  divisible,  as  elsewlicrc,  into  two  layers,  the  tleep  one  being  a  very  deli- 


PLATE 


INCISIONS  FOR  DISSECTION  AND  LINES  FOR  VESSELS  AND  NERVES, 

27 


PLATE 


\ 


External  jugular  v. 


Small  occipital  n.- 

Mascoid  br.  of 
small  occipital  nr 


Great  auricular  n. 


Posterior  jugular  v  ■ 


Superficial  layer 

of  deep  fascia— 


/ 


.\  ■*  , 


^ 


Platysma  myoides  m. 


PLATYSMA  MYOIDES  MUSCLE. 
30' 


DISSFCTIOX  OF  rilE  NECK.  31 

cate  layer  of  laminated  tissue.  Between  these  twn  layers  an-  Uic  ]ilatysma  luyoides 
muscle,  the  external,  anterior,  and  posterior  jugular  veins,  the  sujiertieial  branches 
of  the  cervical  plexus  of  nerves,  and  the  infra-maxillary  branch  of  the  cervico-facial 
division  of  the  facial  nerve.  The  fat  in  the  superficial  fascia  above  the  hyoid  bone 
may  be  extensively  develojieil  and  produce  the  eouilitinn  known  as  "ihiuble  chin." 

Dissection. — The  superlieial  layer  of  (be  superficial  fascia  should  be  removed 
in  the  manner  |)ractised  in  retlectiiit;-  the  skin.  This  disst'ction  expo.ses  the 
platysma  myoides  muscle. 

The  platysma  myoides  muscle  (the  superficial  cervical),  a  Ijroad,  thin  muscle, 
lies  immediately  beneath  the  skin  and  the  superficial  layer  of  the  superficial 
fascia  ;  it  covers  the  front  and  side  of  the  neck,  extending  from  tiie  summit  of  the 
shoulder  and  front  of  the  chest  to  the  face.  Tliis  muscle  is  a  member  of  the  pan- 
niculus  carnosus  group.  It  arises  from  the  deep  fascia  covering  the  pectoralis 
major,  deltoid,  and  trapezius  muscles,  and  ascends  obliquely  forward  along  the  side 
of  the  neck,  for  insertion  into  the  lower  border  of  the  lower  jaw,  the  superficial 
fascia  of  the  cheek,  the  muscles  at  the  angle  of  the  mouth,  and  the  integument  of 
the  chin.  The  anterior  fibers  cross  those  of  the  opposite  side  just  below  the 
symphysis  of  the  lower  jaw,  and  are  inserted  into  the  integument  of  tiie  chin  ;  the 
middle  fibers  are  attached  to  the  lower  border  of  the  lower  jaw  ;  the  posterior 
fibers  are  prolonged  over  the  masseter  muscle,  and  are  inserted  into  the  super- 
ficial fascia  of  the  cheek  and  the  muscles  at  the  angle  of  the  mouth.  Those  fibers 
passing  transversely  to  the  angle  of  the  mouth  constitute  the  risorius  muscle. 

Nerve  Supply. — From  the  infra-maxillary  branch  of  the  cervico-facial  divi- 
sion of  the  facial  and  the  superficial  cervical  nerves. 

Blood  Supply. — From  the  vessels  I'amifying  in  the  superficial  fascia  of  the 
neck. 

Action. — It  dra^vs  the  lower  lip  downward  and  outward  by  contraction  of  its 
upper  fibers ;  when  all  the  fibers  are  contracted,  however,  the  skin  and  superficial 
fascia  of  the  neck  lietween  the  clavicle  and  lower  jaw  are  raised,  being  made  taut 
between  these  two  bones  ;  it  also  helps  to  depress  the  lower  jaw,  or,  if  the  jaw  be 
fixed,  assists  the  opposite  sterno-mastoid  muscle  in  flexion  and  rotation  of  the  head 
toward  its  own  side.  The  anterior  edge  of  the  muscle  is  distinctly  visible  in 
emaciated  and  aged  persons,  forming,  with  the  platysma  of  the  opposite  side, 
two  divergent  folds  descending  from  a  little  l)elow  the  chin.  As  the  mu.scle  dips 
into  a  depression  above  the  clavicle,  by  elevation  of  skin  and  fasciae  at  tlie  loot 
of  the  neck,  it  relieves  press.ure  upon  the  veins  and  favors  the  return  circulation. 

Injuries  of  the  neck,  with  destruction  of  considerable  portions  of  the  integu- 
ment and  platysma,  as  in  burn.s,  areu.sually  followed  by  deformity  from  cicatricial 
contraction.     Pus  in  the  loose  tissues  under  the  platysma  may  burrow  extensively. 


32  SURGICAL  AXATOMV. 

descending  from  the  submaxillary  region  to  the  upper  part  of  the  chest-wall,  Avhere 
pointing  may  occur. 

Dissection. — The  platysma  should  now  be  removed,  cutting  it  across  near  the 
clavicle  and  reflecting  it  upward  to  its  insertion  into  the  jaw,  thus  exposing  the 
subcutaneous  portions  of  the  superficial  branches  of  the  cervical  plexus  of  nerves, 
tlie  infra-inaxillary  branch  of  the  cervico-facial  division  of  the  facial  nerve,  and  the 
anterior,  external,  and  posterior  jugular  veins. 

The  external  jugular  vein  arises  in  the  substance  of  the  parotid  gland,  and  is 
formed  by  the  union  of  the  jiosterior  auricular  vein  and  the  posterior  division  of 
the  temporo-maxillary  vein.  It  runs  down  the  neck  in  a  line  drawn  from  the 
angle  of  the  lower  jaw  to  the  middle  of  the  clavicle,  first  passing  over  the  sterno- 
mastoid  muscle,  and  then  along  its  posterior  border  to  tlie  root  of  the  neck,  there 
piercing  the  sujjerficial  layer  of  the  deep  cervical  fascia  to  enter  the  subclavian 
vein  in  the  subclavian  triangle.  This  fascia  is  so  closely  attached  to  the  A'ein  that 
at  the  root  of  the  neck,  if  the  vein  be  divided,  it  will  remain  open.  The  auricu- 
laris  magnus  nerve,  a  branch  of  the  cervical  plexus,  accompanies  the  vein  in  its 
upper  part,  and  the  superficial  cervical  branch  of  the  same  plexus  passes  beneath 
it  at  about  the  middle  of  the  course  of  the  vein.  The  posterior  external  jugular, 
transversalis  colli,  and  supra-scapular  veins  empty  into  the  external  jugular  vein. 
Near  the  angle  of  the  lower  jaw  the  external  jugular  communicates  with  the 
internal  jugular  vein  bj'  a  large  branch,  farther  down  with  the  anterior  jugular, 
and,  at  times,  with  the  cephalic  vein  by  a  branch  (jugulo-cephalic)  which  passes 
over  the  clavicle.  The  anterior  jugular  vein  occasionallj'  empties  into  the  external 
jugular  instead  of  into  the  subclavian  vein.  The  external  jugular  vein  contains 
a  pair  of  valves  at  its  point  of  entrance  into  the  subclavian,  and  another  pair 
about  one  inch  or  one  and  one-half  inches  above  this  point ;  these  valves  can  not 
prevent  the  reflux  of  blood  into  the  external  jugular  vein,  and  in  certain  cardiac 
and  aortic  diseases,  especially  in  tricuspid  insufficiencj%  a  pulsation  in  the  external 
Jugular  vein  synchronous  with  the  cardiac  systole  may  be  observed.  The  portion 
of  the  vein  between  the  valves  is  dilated  ;  tins  jiortion  is  called  the  sinus.  The 
external  jugular  vein  varies  in  size — when  the  anterior  and  posterior  jugular  veins 
are  large,  the  external  jugular  vein  is  small,  and  vice  versa.  In  some  instances 
two  external  jugular  veins  may  be  observed  ujion  each  side  of  the  neck.  The 
superficial  cervical  nerve  may,  at  times,  be  seen  to  pierce  tlie  wall  of  the  vein. 

Venesection. — Tlie  operation  of  phlebotomy,  or  venesection,  may  be  per- 
formed upon  the  external  jugular  vein,  \\"lien  the  lower  portion  of  the  vein  is 
selected  lor  the  operation,  the  direction  the  fibers  of  the  platysma  myoides  muscle 
sliould  Vie  borne  in  mind,  and  the  incision  be  made  across  tbem.  They  will 
then   retract  and  pull   the  wound  open,  thus  allowing  the  blood  to  flow  freely  and 


11-:^ 


PLATE  V, 


\ 


Small  occipital  n. 

br.  of  small  occipital  n. 

.Inframaxillary  br.  of  facial  n. 


Supraacromial  br.  of  cervical  plexus 


Suprasternal  br.  of  cervical  plexus 
Supraclavicular  branches  of  cervical  plexus 


SUPERFICIAL  LAYER  OF  DEEP  FASCIA,  SUPERFICIAL  VEINS  AND   NERVES, 

34 


PLATE 


Supraorbital  v 
Frontal  veins 


Transverse  facial 
Orbital 


Middle  temporal  v, 

Superficial  temporal  v. 


(Communication  with  mastoid  \ 
Occipital  V. 


Angular  v. 


VEINS  OF  SCALP,  FACE,  AND  NECK. 
35 


DISSECTWX  or  THE  SFJ'K.  37 

avuiilin^-  its  oxtrava.satioii  liciicatli  the  ijlatvsnia.  The  vein  is  incise^l  i-iiiUquely,  not 
transviTst'iy,  and  should  nut  lie  cDiiiiiletely  severed,  as  lieinonhagc  from  a  partially 
divided  vessel  is  mure  copious.  The  hemorrhage  may  be  cliecked  by  relieving  the 
pressure  applied  to  the  vein  at  the  root  of  the  neck,  and  by  application  of  a  sterile 
compress  over  the  wound.  When  the  upper  portion  of  the  external  jugular  is 
selected,  the  incision  should  be  carried  in  the  line  of  the  fibers  of  the  stcnio- 
mastoid  muscle.  The  external  jugular  vein  may  be  selected  as  one  of  llie  chan- 
nels for  the  intra-venous  injection  of  saline  solution. 

A  chain  of  small  lyni]ihatie  glands  (superficial  cervical),  varying  in  munber 
fxiim  four  to  six,  lies  along  the  course  of  the  external  jugular  vein. 

The  posterior  external  jugular  vein  commences  in  the  upper  and  back  part 
of  the  neck,  between  the  sjjlenius  and  trapezius  muscles,  draining  this  territory  and 
entering  the  lower  jiortion  of  the  external  jugular  vein.  It  occasionally  receives 
the  occipital  vein.  In  the  fetus  it  drains  the  intra-cranial  region  through  a  vein 
transmitted  by  the  post-glenoid  foramen,  the  remnant  of  which  vein  is  the  mastoid 
vein.  The  tran-sversalis  colli  and  supra-scapular  veins  frcriuently  emjity  into  the 
posterior  external  jugular  vein. 

The  anterior  jugular  vein  arises  beneath  the  chin.  It  is  formed  by  the 
mental,  submental,  inferior  labial,  and  inferior  hyoid  veins,  and  passes  downward, 
almost  to  the  sternum,  in  advance  of  the  anterior  border  of  the  sterno-mastoid 
muscle.  Here  it  pierces  the  superficial  layer  of  the  deep  cervical  fascia,  and 
occupies  the  interval  (supra-sternal  intra-aponeurotic  space  of  Griiber)  above  the 
sternum,  made  by  the  division  of  the  superficial  layer  of  the  deep  cervical  fascia 
into  two  layers ;  it  then  turns  outward  beneath  the  sterno-mastoid  muscle,  and 
enters  the  external  jugular  or  the  subclavian  vein.  It  drains  the  skin  and  muscles 
of  the  anterior  or  median  region  of  the  neck.  In  making  a  subcutaneous  section 
of  the  sterno-mastoid  muscle  for  the  correction  of  wryneck  (torticollis),  the  teno- 
tome must  hug  the  under  surface  of  the  origins  of  the  muscle  closely,  otherwise 
the  anterior,  external,  and  internal  jugular  veins  may  be  injured.  There  are 
usually  two  anterior  jugular  veins,  one  upon  each  side  of  the  median  line  of 
the  neck,  connected  just  above  the  sternum  by  a  transverse  branch.  This  branch 
also  occupies  the  interval  between  the  two  layers  of  the  superficial  layer  of  the 
deep  cervical  fascia,  and  being  quite  large  at  times,  should  be  borne  in  mind 
when  performing  the  low  operation  of  tracheotomy.  In  labored  breathing,  due 
either  to  laryngeal  or  tracheal  obstruction,  these  veins  will  be  much  dilated,  and 
care  will  be  required  in  incising  the  median  line  of  the  neck,  to  prevent  opening 
one  or  the  other.  Shoul<l  this  accident  occur  in  the  operation  of  tracheotomy, 
while  not  a  serious  complication,  it  may  cause  some  embarrassment.  Division  of 
the  transverse  branch  connecting  the  anterior  jugulars  at  the  root  of  the  neck 


38  SURGICAL   ANATOMY. 

will  occasion  very  free  bleeding ;  this  might  mislead  the  surgeon  in  performing 
his  first  tracheotomy,  leading  him  to  think  that  he  had  opened  an  anomalously 
high  left  innominate  vein.  The  anterior  jugular  vein  contains  no  valves,  and 
its  variation  in  size,  in  inverse  proportion  to  the  other  jugular  veins,  should  be 
remembered. 

Dissection. — Next  trace  the  superficial  branches  of  the  cervical  plexus  and 
the  infra-maxillary  branch  of  the  cervico-facial  division  of  the  facial  nerve. 

The  superficial  branches  of  the  cervical  plexus  of  nerves  are  divided  into 
the  ascending,  transverse,  and  descending  branches.  The  ascending  branches  are 
the  occipitalis  minor  and  auricularis  magnus  nerves.  The  transverse  branch 
is  the  superficial  cervical  nerve.  The  descending  branches  are  the  supra-sternal, 
supra-clavicular,  and  supra -acromial  nerves. 

The  occipitalis  minor  nerve  arises  from  the  anterior  division  of  the  second 
cervical  nerve.  It  forms  beneath  the  sterno-mastoid  muscle  a  loop  which  embraces 
the  spinal  accessory  nerve  ;  it  also  furnishes  a  branch  to  the  spinal  accessory  nerve, 
and  emerges  from  beneath  the  posterior  border  of  the  sterno-mastoid  just  above 
the  middle  of  the  muscle.  This  loop  acts  as  a  guide  in  locating  the  spinal 
accessory  nerve.  The  occipitalis  minor  nerve  ascends  along  the  upper  half  of  the 
posterior  border  of  the  sterno-mastoid  muscle  to  the  occiput,  where  it  pierces  the 
superficial  layer  of  the  deep  cervical  fascia.  It  is  distributed  to  the  integumen 
covering  the  occipitalis  muscle,  and  communicates  with  the  great  occipital,  the 
auricularis  magnus,  and  the  posterior  auricular  branch  of  the  facial  nerve.  It 
also  gives  off"  an  auricular  branch  which  supplies  the  skin  of  the  upper  and  back 
part  of  the  auricle. 

The  auricularis  magnus  nerve,  the  largest  of  the  superficial  branches 
of  the  cervical  plexus,  arises  from  the  anterior  division  of  the  second  and  third 
cervical  nerves,  and  curves  around  the  posterior  border  of  the  sterno-mastoid 
muscle  immediately  above  the  superficial  cervical  nerve.  Here  it  pierces  the 
superficial  layer  of  the  deep  cervical  fascia,  ascends  in  relation  with  the  upper  part 
of  the  external  jugular  vein,  and  passes  obliquely  over  the  sterno-mastoid  and 
beneath  the  platysma  myoides  muscle.  Reaching  the  lobule  of  the  ear  it  divides 
into  the  following  branches :  a  facial  or  anterior,  distributed  to  the  skin  over 
the  parotid  gland,  and  communicating  with  branches  from  the  facial  nerve 
through  this  gland,  which  it  also  supplies  ;  an  auricular  or  posterior,  distributed  to 
the  integument  on  the  back  of  the  auricle,  and  communicating  with  the  posterior 
auricular  branch  of  the  facial  and  the  auricular  branch  of  the  pneumogastric 
nerve  ;  and  a  mastoid  branch,  distributed  to  the  skin  ovcr  the  mastoid  process, 
communicating  with  the  occipitalis  minor  and  the  posterior  auricular  branch  of 
the  facial  nerve. 


PLATE 


Esophagus 


Trachea 
Sterno-thyroid  m 
Thyroid  body 
Longus  colli  ni 
Sterno-hyoid  rn 
Sterno-mastoid  m 


.Pretracheal  fascia 

Superficial  layer  of  deep  fascia 
Anterior  jugular  v. 
Prevertebral  fascia 


scapulae  m. 
Cervicalis  ascendens 
m 
Transversalis  colli  m 

Splenius  m 

Complexus  m 
Semispinalis  colli  m' 
Multifidus  spinae 


Superficial 

ayer  of 
deep  fascia 

'Ant.div.of  5th  cervical  n. 

Ant.div.uf  6th  cervical  n. 
Vertebral  a. and  veins 


Ligamentum  nuchae 


SECTION  OF  NECK  AT  SIXTH  CERVICAL  VERTEBRA. 
39 


* 


PLATE 


Pretracheal  fascia 
Prevertebral  fascia 
Descendens  hypoglossi  n 


Superficial  laye 
of  deep  fascia 


Superficial  layer  of  deep  fascia 

Common  carotid  a. 
Pneumogastric  n. 
Internal  jugular  v. 


Ligamentum    nuchae 


DIAGRAM  OF  DEEP  CERVICAL  FASCIA. 
41 


PLATE  IX. 


N.to 

ff\CA  minor 


CERVICAL  PLEXUS, 
.  44 


DISSECTION  OF  THE  NECK.  45 

Tlie  superficial  cervical  nerve  (suiHTlie-ialis  ccilli)  is  a  lirancli  of  the  anterior 
divisions  of  tlie  seeoiul  ami  tliM'd  cervical  norves.  It  winds  around  tlu'  niiildic  of 
tlie  posterior  border  of  the  sterno-niastoid  muscle,  pierces  tlie  superlicial  layer  of 
the  deep  cervical  fascia,  and  passes  transversely  over  the  muscle  beneath  the 
external  jugular  vein,  receiving  a  communicating  branch  from  the  infra-maxillary 
branch  of  the  facial  nerve.  It  divides  into  an  ascendint/  and  a  desmnliii;/  hrancJi  ; 
the  fornu-r  sends  tilaments  to  the  external  jugular  vein,  conununicates  witli  tlie 
infra-maxillary  branch  of  the  facial  nerve,  and  supplies  the  platysma  niyoides 
muscle  and  the  skin  of  the  front  of  the  neck  as  far  as  the  clun  ;  the  latter 
supplies  the  skin  of  the  lower  half  of  the  front  of  the  neck. 

The  descending  branch  of  the  plexus  arises  from  the  anterior  divisions  of  the 
third  and  fourth  cervical  nerves,  emerges  from  beneath  the  i)0sterior  border  of  the 
sterno-mastoid  muscle,  pierces  the  superficial  layer  of  the  deep  cervical  fascia,  and 
divides  into  the  supra-sternal,  supra-clavicular,  and  supra-acromial  nerves.  The 
inner  or  supra-sternal  twigs  pass  over  the  clavicular  and  sternal  origins  of  the 
sterno-mastoid  muscle,  and  sujiply  the  integument  over  the  inner  end  of  the  clavicle 
and  the  upper  part  of  the  sternum  ;  the  middle  or  supra-clavicular  branches  cross 
the  middle  of  the  clavicle,  supply  the  integument  ovei'  the  upper  fore  jiart  of  the 
deltoid  and  u[>per  part  of  the  pectoralis  major  muscle  and  the  mammaiy  glaml, 
and  communicate  with  the  small  cutaneous  branches  of  the  upper  interco.stal 
nerves  ;  the  external  or  supra-acromial  branches  cross  the  upper  surface  of  the 
trapezius  muscle  and  the  acromion  process,  and  supply  the  integument  of  the 
upper,  outer,  and  back  part  of  the  shouldei'.  Herpetic  erujitions  in  the  area  of 
distribution  of  the  superficial  branches  of  the  cervical  plexus  (herpes  cervico- 
occipitalis)  are  occasionally  seen.  In  caries  of  the  cervical  vertebrje  pain  may  be 
referred  to  the  areas  of  skin  supplied  by  these  nerves.  It  is  through  the  descend- 
ing branches  of  the  cervical  plexus  that  pain  is  referred  to  the  neck  in  carcinoma 
of  the  mammary  gland. 

The  infra-maxillary  branch  of  the  cervico-facial  division  of  the  facial 
nerve  emerges  from  the  lower  border  of  the  parotid  gland,  and  passes  downward 
and  forward  under  the  platysma  myoides  muscle,  which  it  supplies,  and  commu- 
nicates with  the  sujierticial  cervical  nerve. 

The  deep  cervical  fascia,  like  the  deep  fascia  in  other  portions  of  the  body, 
consists  of  a  superficial  layer  which  surrounds  the  underlying  muscles,  vessels,  and 
nerves,  and  of  processes  prolonged  inward  to  form  separate  sheaths  for  the  mus- 
cles and  vessels,  thus  i.?olating  and  helping  to  retain  them  in  their  ]iro])er  positions. 
It  varies  in  strength,  being  strongest  below  tlie  angle  of  the  lower  jaw,  above  the 
clavicle,  and  in  front  of  the  trachea.  In  studying  this  fascia  it  will  be  found  more 
satisfactory  to  trace  it  from  behind,  where  it  is  attached  to  the  ligamentum  nuehse 


46  SURGICAL  ANATOMY. 

and  the  spinous  process  of  the  seventh  cervical  vertebra  (vertebra  prominens).  At 
the  ligamentum  nuchse  the  superficial  layer  immediately  begins  as  two  layers, 
whicli  inclose  the  trapezius  muscle.  From  the  anterior  border  of  the  trapezius  it 
passes  as  a  single  laj'er  across  the  posterior  triangle  of  the  neck  to  the  posterior 
border  of  the  sterno-mastoid  muscle.  This  portion  of  the  superficial  laj'er  is 
attached  above  to  the  mastoid  process  of  the  temporal  and  superior  curved  line  of 
the  occipital  bone,  and  below  to  the  clavicle.  It  is  pierced  by  the  external  jugular 
vein  directly  above  the  clavicle,  behind  the  clavicular  origin  of  the  sterno-mastoid 
muscle.  At  the  posterior  border  of  the  sterno-mastoid  muscle  it  again  splits  into 
two  layers  to  inclose  the  muscle,  from  the  anterior  border  of  which  it  is  continued 
as  a  single  layer  across  the  anterior  triangle  of  the  neck  to  the  middle  line,  where 
it  joins  the  corresponding  layer  of  fascia  of  the  opposite  side.  This  portion  of  the 
superficial  layer  is  attached  above  to  the  lower  border  of  the  lower  jaw  and  the 
styloid  process  of  the  temporal  bone,  and  in  front  to  the  hj'oid  bone.  Near  the 
upper  border  of  the  sternum  this  layer  of  fascia  divides  into  two  laj'ers,  an  ante- 
rior and  a  posterior,  which  are  attached  respectively  to  the  anterior  and  posterior 
margins  of  the  upper  border  of  the  sternum.  Between  these  two  layers  is  an 
interval  (the  supra-sternal  intra-aponeurotic  space  of  Griiber)  containing  some  fat, 
perhaps  one  or  two  small  Ij'mphatic  glands,  the  sternal  head  of  the  sterno-mastoid 
muscle,  the  anterior  jugular  veins,  and  the  transverse  branch  connecting  them. 
The  la3'er  of  fascia  overlying  the  sterno-mastoid  muscle  is  continued  upon  the  face 
over  the  parotid  gland  and  the  masseter  muscle  as  the  parotid  and  masseteric 
fasciae,  which  are  attached  to  the  lower  border  of  the  zj'gomatic  arch. 

The  portion  of  the  superficial  laj^er  covering  the  trapezius  and  sterno-mastoid 
muscles  is  so  thin  that  their  fibers  can  be  seen  through  the  fascia.  At  the  angle 
of  the  lower  jaw  this  layer  of  fascia  sends  a  process  inward  which  is  attached  to  the 
styloid  process,  and  is  known  as  the  stylo-maxillary  ligament.  This  ligament 
sej)arates  the  parotid  from  the  submaxillary  gland.  From  the  superficial  layer 
two  processes  are  given  off,  a  posterior  and  an  anterior.  The  posterior  process 
(jjrevertebral  fascia)  arises  from  the  suj)erficial  layer  at  the  anterior  border  of  the 
trapezius  muscle,  and  covers  the  splenius,  levator  anguli  scapulas,  scaleni  and 
prevertebral  muscles,  subclavian,  vertebral,  inferior  thyroid,  supra-scapular,  and 
transversalis  colli  ves.sels,  cervical  trunks  of  the  axillary  or  brachial  plexus, 
phrenic  nerve,  and  cervical  sympathetic  nerve.  This  process  of  fascia  passes 
lirliiud  the  cf)iiinion  carotid  artery,  inli'rnal  jugular  vein,  pharynx,  and  esophagus. 
It  is  attached  above  to  the  base  of  tlic  skiiU  ;  below,  to  tlie  first  rib,  a^  far  forward 
as  the  anterior  margin  of  the  scalenus  anticus  muscle.  To  the  inner  side  of  this 
muscle  it  jiasses  downward  into  the  chest  over  the  longus  colli  muscle  and  bodies 
of  the  vertebrtc.     To  the  outer  side  of  the   scalenus  anticus  muscle  it  splits  to 


DISSECTIOX  OF  THE  NECK.  47 

envelop  the  subclavian  vessels,  which  it  accompanies  into  the  axilla,  where,  with 
a  process  from  the  costo-coracoid  membrane,  it  forms  the  sheath  of  the  axillary 
vessels.  As  it  passes  behind  the  common  carotid  artery  and  internal  juf;ular  vein 
it  reinforces  the  sheath  of  these  vessels.  The  anterior  process  (pretracheal  fascia) 
arises  from  the  superficial  layer  near  the  anterior  border  of  the  sterno-mastoid 
muscle,  passes  beneath  the  sterno-hyoid  and  .sterno-thyroid  muscles,  and  in  lioiit 
of  the  trachea,  enveloping  the  tliyroid  gland.  It  is  attached  Id  tlic  first  ril),  to 
which  it  binds  the  tendon  of  the  omo-hyoid  mu.scle.  This,  with  the  posterior 
process  just  described,  and  the  layer  of  deep  fascia  beneath  the  sterno-mastoid 
muscle,  complete  the  formation  of  the  sheath  of  the  common  carotid  artery  and 
internal  jugular  vein.  The  portion  of  the  deep  cervical  fascia  wliich  envelo]is 
the  trachea  and  great  vessels  extends  downward  along  the  great  vessels  into  the 
chest,  where  it  is  continuous  with  the  fibrous  layer  of  the  pericardium. 

The  superficial  laj'er  of  the  deep  cervical  fascia,  with  its  two  dceji  processes, 
divides  the  neck  into  three  compartments  :  an  anterior,  a  middle,  and  a  posterior. 
The  anterior  compartment,  between  the  superficial  layer  and  the  pretracheal  fascia, 
contains  the  anterior  belly  of  the  omo-hyoid,  the  sterno-hyoid,  and  sterno-thyroid 
muscles.  The  middle  or  visceral  compartment,  between  the  pretracheal  and  ]  ire- 
vertebral  fasciae,  contains  the  thyroid  gland,  trachea,  and  esophagus.  The  posterior 
or  muscular  compaiiment,  between  the  prevertebral  fascia  and  the  superficial 
layer,  contains  the  prevertebral  muscles,  scaleni,  levator  anguli  scapulte,  and  the 
muscles  of  the  back  of  the  neck,  excepting  the  trapezius. 

Dr.  Allan  Burns  first  called  the  attention  of  the  profession  to  the  Ijarrier  at  the 
upper  opening  of  the  chest,  formed  by  the  attachment  of  the  deep  cervical  fascia 
to  the  sternum,  the  first  rib,  and  the  clavicle,  supporting  the  soft  parts  and 
preventing  them  from  yielding  to  the  pressure  of  the  atmosphere  during  ins])ira- 
tion.  The  internal  jugular,  subclavian,  and  innominate  veins  are  so  closely 
attached  to  the  adjacent  bones  and  muscles  by  the  deep  cervical  fascia  that  they 
gape  when  divided,  thus  permitting  air  to  enter.  In  operations  on  the  neck,  mIuii 
these  veins  are  exposed  and  division  is  necessary,  it  is  best  to  ligate  tliem  before 
severing  them. 

Abscess. — In  order  to  become  familiar  with  the  course  pus  jiursues  in  the 
neck,  a  correct  knowledge  of  the  attachments  of  the  deep  cervical  fascia  is  neces- 
sary. A  collection  of  pus  situated  beneath  the  superficial  layer  of  the  deep  fascia  at 
the  side  of  the  neck  may  burrow  into  the  axilla,  and,  vice  versa,  one  in  the  axilla 
may  work  its  way  into  the  neck  ;  if  situated  beneath  the  layer  of  deep  fascia  (pos- 
terior process  or  prevertebral  fascia)  covering  the  scaleni  muscles,  and  attached  to 
the  first  rib  as  far  forward  as  the  anterior  border  of  the  anterior  scalene  muscle, 
it  mav  burrow  into  the  chest  cavity,  reaching  the  posterior  mediastinum,  or  follow 


48  SURGICAL  ANATOMY. 

the  sheath  of  the  subclavian  vessels  into  the  arm-pit ;  if  situated  beneath  the  super- 
ficial layer  of  the  deep  fascia  in  the  anterior  portion  of  the  neck,  it  may  enter  the 
chest,  being  guided  into  the  anterior  mediastinum  by  the  pretracheal  fascia  ;  if  it 
lie  beneath  the  anterior  process,  or  pretracheal  fascia,  it  may  extend  into  the 
posterior  mediastinum.  Abscesses  of  the  neck  have  frequently  burst  into  the 
esophagus  or  trachea,  and  even  into  the  pleural  sac  ;  the  great  vessels  at  the  side 
of  the  neck  have  in  some  instances  been  entered.  "  In  one  remarkable  case, 
reported  by  Mr.  Savory,  not  only  was  a  considerable  portion  of  the  common 
carotid  arterj'  destroyed  by  the  abscess,  but  a  still  larger  portion  of  the  internal 
jugular  vein  and  a  large  part  of  the  vagus  nerve  were  also  destroyed  "  (Treves). 
Mr.  Jacobson  (Hilton,  on  "  Rest  and  Pain  ")  states  that  "  communication  between 
abscesses  and  the  deep  vessels  has  usually  taken  place  beneath  two  of  the  strongest 
fasciaj  in  the  body — the  deep  cervical  and  the  fascia  lata."  Prompt  evacuation 
is  indicated  by  the  possibility  that  these  absce.sses  may  take  one  or  more  of  the 
foregoing  undesirable  courses. 

Dissection. — The  superficial  laj'er  of  the  deep  fascia  should  be  removed  by 
making  incisions  similar  to  those  made  for  the  removal  of  the  skin  and  the  super- 
ficial foscia,  being  careful  not  to  destroy  the  superficial  branches  of  the  cervical 
plexus  of  nerves  which  pierce  it.  The  removal  of  the  superficial  layer  will  expose 
its  two  processes  and  other  underlying  structures. 

Cervical  plexus. — Before  taking  up  the  description  of  the  muscles  of  the 
neck  and  its  dissection  proper,  the  origins  of  the  superficial  branches  of  the  cervical 
plexus  of  nerves  should  be  studied.  This  plexus  is  formed  by  the  communi- 
cation of  the  anterior  divisions  of  the  upper  four  cervical  nerves,  all  of  Avhich 
communicate  with  the  sympathetic  nerve.  It  lies  viiider  the  sterno-mastoid 
muscle,  opposite  the  upper  four  cervical  vertebrae,  and  rests  upon  the  levator 
anguli  scapulae  and  scalenus  medius  muscles.  Its  branches  consist  of  a  superficial 
and  a  deep  set.  The  superficial  branches,  as  previously  described,  are  the  auricu- 
laris  magnus,  the  occipitalis  minor,  the  superficial  cervical,  the  supra-sternal,  the 
supra-clavicular,  and  the  supra-acromial,  all  running  to  the  skin  and  subcutaneous 
structures.  The  deep  branches  are  the  phrenic,  the  communicantes  hypoglossi, 
communicating,  and  muscular.  The  superficial  branches  alone  concern  us  in  this 
stage  of  the  dissection.  They  emerge  at  the  side  of  the  neck  from  beneath  the 
])osterior  border  of  the  sterno-mastoid  muscle,  at  the  level  of  tlie  upper  border 
of  the  thyroid  cartilage. 

Till'  sterno-cleido-mastoid  muscle,  the  largest  muscle  of  the  neck  and  its 
most  important  landmark,  arises  by  two  heads:  one,  round  and  tendinous,  from 
the  front  of  the  uppei"  portion  of  tlu;  sternum  ;  the  other,  flattened,  partly 
muscular  and   partly  tendinous,   from  the  inner  one-third  of  the  ui)pcr  surface 


II-4 


PLATE  X, 


External  carotid 

Internal  maxillary 
Temporal  v. 
Posterior  auricular  a 
Posterior  auricular  v. 


Complexus 


Stylo-hyoid  m. 

Posterior  belly  of  digastric  m. 
Occipital  a. 
.Lingual  V. 

Lingual  a. 
Facial  V. 


Anterior  bellies  of 
digastric  muscles 


Levator  anguli  scapulae  m 

Ttansvcrsalis  colli  v. 

Serrotus  magnus 

Postencr  belly  of  omo-hy 

Scalenus  modius  m 


Suprascapular  a. 
Suprascapular  v. 
Subclavian  a. {3d  portion) 
Transversalis  colli  a. 


Stcrno-thyroid  m. 


SUPERFICIAL  STRUCTURES  OF  NECK. 
50 


PLATE  XI, 


Facial  n. 
Posterior  auricular  n.and  v. 


Nerve  to  stylo-hyoid  m.and  posterior  belly  of  digastric  m, 
Hypoglossal  n. 

Descendens  hypoglossi  n. 
Lingual  V. 

SulDmaxillary  gland 
Mylo-liyoid  n. 


Superficial  cervical  n 
Posterior  thoracic  n 

Suprascapular  n. 


Brachial  plexus 


SUPERFICIAL  8   -  S  OF  NECK. 

51 


DISSECTION  OF  THE  NECK.  r^S 

of  the  clavicle.  These  two  heads  unite  at  a  variable  distance  from  tlic  clavicle. 
Tiie  muscle  is  inserted  into  the  external  surface  of  the  inastnid  pi'occss  (if  llie 
temporal  bone  by  a  strong,  thick  tendon,  and  into  the  outer  twothirds  of  tlie 
superior  curved  line  of  the  occipital  bone  by  a  thin  aponeurosis.  Tlie  muscle 
is  narrower  in  the  middle  than  at  either  extremity.  Its  anterior  border  is  the 
surgeon's  guide  in  the  ligation  of  the  common,  external,  and  internal  carotid  arteries, 
the  superior  thyroid,  lingual,  facial,  and  occipital  arteries  at  their  origin,  and  the 
inferior  thyroid  artery  as  it  enters  the  thyroid  gland  ;  in  ex])osing  tlu'  s]iiiia]  acces- 
sory nerve  ;  upon  the  left  side  in  tlu;  operation  of  esophagotoni}^ ;  and  in  all  other 
operations  upon  the  front  of  the  side  of  the  neck.  The  jiosterior  border  of  the 
muscle  is  a  guide  in  the  ligation  of  the  subclavian  and  vertebral  arteries ;  the 
inferior  thyroid  artery  at  its  origin  ;  in  stretching  the  spinal  accessory  nerve,  the 
superficial  branches  of  the  cervical  ])lexus,  and  the  cervical  trunks  of  the  brachial 
or  axillary  jilexus ;  and  in  all  other  operations  upon  the  posterior  portion  of  the 
side  of  the  neck. 

Blood  Supply. — From  the  superior,  middle,  and  inferior  sterno-mastoid  arte- 
ries. The  superior  sterno-mastoid  is  a  branch  of  the  occipital  artery,  and  enters 
the  muscle  with  the  spinal  accessory  nerve  ;  the  middle  sterno-mastoid  is  a  branch 
of  the  superior  thyroid  artery,  and  enters  the  middle  one-tliird  of  tlie  muscle, 
after  crossing  the  .sheath  of  the  common  carotid  artery  in  the  sujx'rior  carotid 
triangle  on  a  level  with  the  thyroid  cartilage ;  the  inferior  sterno-mastoid  is  a 
branch  of  the  supra-scapular  arter}',  and  enters  the  lower  one-third  of  the  muscle. 
The  muscle  also  receives  a  twig  from  the  posterior  auricular  artery. 

Nerve  Supply. — From  the  spinal  accessory  and  the  anterior  divisions  of  the 
second  and  third  cervical  nerves. 

Action. — The  combined  action  of  the  sterno-mastoid  muscles  is  to  draw  the 
head  forward,  elevating  the  chin  at  the  same  time  ;  when  one  muscle  alone  acts,  it 
turns  the  face  to  the  opposite  side,  cooperating  with  the  opposite  splenius  muscle  ; 
it  also  draws  the  head  toward  the  shoulder  of  the  same  side.  If  the  head  be  fixed, 
these  muscles  will  raise  the  sternum,  as  in  forced  respiration. 

Torticollis. — Permanent  contraction  of  one  of  the  sterno-mastoid  muscles  con- 
stitutes torticollis  (wTyneck).  The  deep  muscles  of  the  neck — splenius  capitis 
et  colli,  complexus,  superior  oblique,  inferior  oblique,  and  rectus  capitis  posticus 
major — may  also  be  involved  in  this  deformity,  particularly  in  cases  of  long 
standing. 

In  true  congenital  wryneck,  due  possibly  to  faulty  position  of  thi'  fetus  in 
utero,  the  sterno-mastoid  muscle  has,  in  some  instances,  been  found  to  be  abnor- 
mally short.  Some  cases  of  wryneck  are  doubtless  due  to  laceration  of  the 
muscle  during  birth,  with  subsequent  cicatricial  contraction.     Facial  asymmetry 


54  SURGICAL  ANATOMY. 

and  deformities  of  tlie  cervical  portion  of  the  spinal  column  may  be  associated  with 
long-standing  cases  of  torticollis.  In  spasmodic  wryneck  the  sterno-cleido-mastoid 
muscle  is  at  fault,  through  the  spinal  accessory  nerve,  though  some  of  the  muscles 
previously  mentioned,  as  well  as  the  trapezius  muscle,  may  be  involved ;  resection 
of  the  spinal' accessory  and  branches  of  the  posterior  divisions  of  the  cervical 
nerves  has  been  performed  in  these  cases.  It  should  not  be  forgotten  that 
irritation  of  some  of  the  cervical  nerves,  as  by  inflamed  lymph  glands  and 
caries  of  the  cervical  vertebrae,  may  cause  a  faulty  position  of  the  head  which 
may  be  mistaken  for  torticollis  due  to  other  conditions. 


TRIANGLES  OF  THE  NECK. 

The  sterno-mastoid  muscle,  owing  to  its  oblique  position,  divides  each  half 
of  the  neck  into  two  triangles — the  anterior  and  posterior  common  triangles. 
The  Anterior  Common  Triangle  is  bounded  above  by  the  lower  border  of  the 
body  of  the  lower  jaw  and  a  line  extending  from  the  angle  of  the  lower  jaw 
to  the  mastoid  process  of  the  temporal  bone  ;  in  front,  by  a  line  extending  from 
the  symphysis  of  the  lower  jaw  to  the  middle  of  the  supra-sternal  notch,  or  by 
the  median  line  of  the  neck  ;  and  behind,  bj'  the  anterior  border  of  the  sterno- 
mastoid  muscle ;  its  apex  is  below — at  the  sternum.  This  triangle  is  subdivided 
into  three  smaller  ones  by  the  posterior  belly  of  the  digastric  muscle  and  the 
anterior  belly  of  the  omo-hyoid  muscle.  The  three  triangles,  from  above  down- 
ward, are  the  submaxinary  or  diffastric,  the  superior  carotid,  and  the  inferior 
carotid.  The  Posterior  Common  Triangle  is  bounded  in  front  by  the  posterior 
border  of  the  sterno-mastoid  muscle  ;  behind,  by  the  anterior  border  of  the 
trapezius  muscle  ;  and  below,  by  the  clavicle ;  its  apex  is  above — at  the  occiput. 
This  triangle  is  subdivided  into  two  smaller  triangles  I\y  the  posterior  belly  of 
the  omo-hyoid  muscle,  the  upper,  the  larger  of  the  two,  being  known  as  the 
occipital,  and  the  lower,  the  smaller,  as  the  subclavian,  triangle. 

The  author  would  here  remind  the  reader  that  the  boundaries  of  these  tri- 
angles by  muscular  margins  do  not  harmonize  witli  the  enumeration  of  their 
contents,  many  of  wliich  are  overlapped  by  the  boundary  muscles,  particularly  the 
sterno-mastoid,  and  are,  therefore,  really  outside  the  spaces  to  which  they  are  thus 
inaccurately  accredited.  The  most  accurate  dividing  line  between  the  anterior 
and  posterior  triangles  would  be  the  middle  line  of  the  sterno-mastoid  muscle 
rather  than  its  two  borders. 

Dissection. — Having  mai)]>ed  out  flic  triangles  into  wliirli  (lie  side  of  the 
neck  is  divided,  tlic  <lissccli(in  (if  tlic  imliviiKinl  ti'iangles  slmuld  next  lie  made, 
coninuTiciiig  with  the  occipital,  the  largest.     Alter  reflecting  tlie  superflcial  layer 


PLATE  XII. 


DIAGRAM  OF  TRIANGLES  OF  NECK. 


05 


DISSECTION  OF  THE  NECK.  57 

of  tlio  deep  cervical  foseia  wliirli  lorins  the  roof  of  tlie  occipital  tiianulc,  the  lat 
and  areolar  tissue  occupying;  tlie  trian<;-le  sliould  be  dissected  mit,  tlius  cxiiusini;- 
its  contents  and  the  posterior  jirocess  of  tlie  deep  cervical  fascia  wliich  covci-s  tlic 
muscles  forminc;  its  floor. 

The  occipital  triangle. — The  occipital  triangle  is  bounded  in  fimit  by  the 
sterno-cleido-mastoid  muscle;  behind,  by  the  trapezius  muscle;  below,  by  tbr  pos- 
terior belly  of  the  omo-byoid  muscle.  Its  roof  is  formed  by  the  suiKTlirial  layer 
of  the  deep  cervical  fascia,  covered  by  the  platysma  myoides  muscle,  superficial 
fascia,  and  skin.  AVIien  the  sterno-mastoid  and  trapezius  mu.scles  do  not  meet  at 
the  apex  of  the  triangle,  a  small  portion  of  the  occipital  artery  may  be  seen  in  the 
interval  between  the  splenius  and  trapezius  muscles.  Crossing  the  triangle 
obliquely  downward  and  backward  from  beneath  the  sterno-mastoid  muscle  are  the 
spinal  accessory  nerve  and  the  branelu's  of  the  third  and  fourth  cervical  nerves, 
which  enter  the  lower  part  of  the  trapezius  muscle  to  su])ply  it.  Emerging  from 
beneath  the  posterior  border  of  the  sterno-mastoid  muscle  are  the  superficial 
branches  of  the  cervical  j)lexus  of  nerves,  which  leave  the  triangle  by  piercing  its 
roof.  Occasionally  the  middle  sterno-mastoid  arteiy  terminates  in  this  triangle. 
Running  along  the  posterior  border  of  the  sterno-mastoid  muscle  is  a  ebain  of  lym- 
phatic glands  ;  this  is  kno\vn  as  the  post-cervical  chain,  and  is  of  special  ini]iortance 
in  the  diagnosis  of  early  secondary  syphilis.  Crossing  the  lower  part  of  tlie  triangle 
is  the  transversalis  colli  artery  and  its  companion  vein.  The  superficial  cervical 
artery,  one  of  the  terminal  branches  of  the  transversalis  colli,  usually  occupies 
the  posterior  inferior  angle  of  this  space  ;  it  runs  upward,  parallel  with  the 
anterior  border  of  the  trapezius  muscle,  but  is,  in  .some  instances,  concealed  by 
the  anterior  border  of  the  trapezius  muscle.  At  the  anterior  inferior  angle  of  the 
triangle  the  upper  part  of  the  brachial  plexus  may  be  seen.  Branches  of  the 
third  and  fourth  cervical  nerves  cross  the  floor  of  the  triangle  to  .supply  the 
levator  anguli  scapulte  muscle. 

The  muscles  forming  the  floor  of  the  occipital  triangle  are,  from  altove  down- 
ward, the  splenius  capitis,  the  levator  anguli  scapulae,  the  scalenus  medius,  and 
the  scalenus  posticus  muscle,  wliich  can  not  be  seen,  however,  until  tlic  posterior 
process  of  the  deep  cervical  fascia  is  removed. 

The  spinal  accessory  nerve. — This  nerve  is  the  mo.st  important  of  tlie 
contents  of  the  occipital  triangle.  It  is  the  eleventh  cranial  nerve,  and  consists  of 
two  parts — the  accessoiy,  from  the  medulla  oblongata,  and  the  .«pinal,  fn>iii  the 
cervical  i)()rtion  of  the  spinal  cord  as  low  as  tlie  sixth  or  seventh  cervical  nerve. 
The  spinal  portion  passes  upward  througli  the  spinal  canal  between  the  ligamentum 
denticulatum  and  the  posterior  roots  of  the  spinal  nerves,  and  enters  the  cranial 
cavity  through  the  foramen  magnum  to  join  the  accessory  portion.     The  two  por- 


58  SURGICAL  ANATOMY. 

tions  emerge  from  the  cranial  cavity  together  through  the  jugular  foramen,  just 
external  to  which  the  accessory  portion  joins  the  ganglion  of  the  root  of  the  pneu- 
mogastric  nerve.  The  spinal  portion  then  passes  successively  behind  the  internal 
jugular  vein,  the  posterior  belly  of  the  digastric,  and  the  stylo-hyoid  muscle,  to 
enter  the  upper  part  of  the  sterno-mastoid  muscle,  entering  its  under  surface  mid- 
waj'  between  its  two  borders  and  one  inch  below  the  tip  of  the  mastoid  process. 
It  leaves  the  muscle  at  the  middle  of  the  posterior  border.  AVithin  the  sterno- 
mastoid  muscle  it  is  joined  by  a  liranch  of  tlie  second  cervical  nerve.  The  superior 
sterno-mastoid  artery  accompanies  the  nerve  into  the  muscle,  which  it  supplies. 
Having  pierced  the  sterno-mastoid  muscle,  it  crosses  the  occipital  triangle 
oblicjuely  downward  and  backward  to  enter  and  supply  the  trapezius  muscle. 

For  the  relief  of  spasmodic  torticollis,  resection  of  a  portion  of  the  spinal 
accessory  nerve  may  be  performed.  The  sj^inal  accessory  nerve  may  be  exposed  at 
one  of  three  points — just  before  it  enters  the  sterno-mastoid  muscle,  in  the  substance 
of  the  muscle,  or  at  the  posterior  border  of  the  muscle.  Of  these  methods,  the  first 
is  the  best.  To  expose  the  .nerve  before  it  enters  the  muscle,  the  head  and  neck 
should  be  well  extended,  and  an  incision  made  along  the  anterior  border  of  the 
upper  one-third  of  the  muscle,  dividing  skin,  sui^erficial  fascia,  some  fibers  of  the 
platysma  myoides  muscle,  and  the  superficial  layer  of  tlie  deep  fascia,  avoiding, 
if  possible,  the  external  jugular  vein.  Displace  the  sterno-mastoid  muscle  out- 
ward, when  the  nerve  will  be  found  beneath  the  prevertebral  fascia  and  passing 
from  beneath  the  sheath  of  the  internal  jugular  vein,  to  enter  the  muscle  about 
an  inch  below  the  tip  of  the  mastoid  process.  The  prominent  transverse  process 
of  the  atlas  lies  above  the  nerve,  and  serves  as  a  deep  guide  in  locating  it. 

To  expose  the  nerve  in  the  substance  of  the  sterno-mastoid  muscle  an  incision 
should  be  made  in  the  middle  line  of  the  nmscle.  Tlic  muscle  fibers  are  separated 
and  the  nerve  exposed  as  it  passes  through  the  deejier  portion  just  above  the  level 
of  the  thyroid  cartilage.  The  skin,  superficial  fascia,  fibers  of  the  platysma  myoides 
muscle,  superficial  layer  of  the  deep  fascia,  the  sterno-mastoid  muscle,  and  the 
superior  and  middle  .sterno-mastoid  arteries  M'ill  lie  cut.  The  external  jugular 
vein  should,  if  possible,  be  avoided. 

To  expose  the  nerve  along  the  posterior  border  of  the  muscle  carry  an  incision 
along  the  middle  one-third  of  that  border.  The  skin,  superficial  fascia,  fibers  of 
the  platysma  myoides  muscle,  and  the  superficial  layer  of  the  deep  fascia  will  be 
divided.  The  occipitalis  minor  nerve  will  be  seen  running  upward  along  the  pos- 
ti'rior  border  of  the  sternp-mastnid  muscle.  Trace  this  nerve  downward,  and  locate 
tlic  spinal  acces.sory  nerve  as  it  emerges  from  the  postci'ior  l)nr(l('r  of  the  sterno- 
mastoid  muscle  on  a  level  wit):  tlie  upiier  border  of  the  thyroid  cartilage. 

The  middle  sterno-mastoid  artery. — The  middle  .sterno-mastoid  artery  will 


DISSECTION  OF  rilK  NECK.  59 

at  times  be  of  considerable  size  and  extend  well  into,  if  not  across,  the  occiiiital 
triangle,  supplyin<x  the  lyiiiiiliatic  glands  and  connective  tissue  contained  therein. 
When,  on  opening  an  abscess  in  this  triangle,  more  than  the  usual  amount  of 
bleeding  follows,  the  probability  is  that  an  anomalously  large  middle  sterno- 
mastoid  artery  has  been  severed.  Under  these  circumstances  the  incision  should 
be  enlarged  to  suflicicntly  expose  both  ends  of  tlu;  bleeding  vessel  and  permit 
their  ligation.  The  author  recalls  a  case  in  \\liich  this  accident  occurred, 
and  the  surgeon,  believing  that  but  a  small  subcutaneous  vessel  had  ])een  iHvidcd, 
relied  on  a  compress,  and  the  patient  died  from  hemorrhage.  Tlu^  autop.sy  I'e- 
vealed  a  severed  large  middle  sterno-mastoid  artery. 

The  transversalis  colli  artery  terminates  in  the  lower  part  of  this  ti'iangle, 
by  dividing  into  the  superficial  cervical  and  the  posterior  scai)idar  artery.  The 
superficial  cervical  artenj  has  lieen  traced  to  the  anterior  1)order  of  the  trapezius 
muscle,  beneath  which  it  anastomoses  with  the  superficial  branch  of  the  princeps 
cervicis  artery.  The  posterior  scapular,  occasionally  a  branch  of  the  third  jiart  of 
the  subclavian  artery,  passes  beneath  the  levator  anguli  scapulae  muscle,  then  along 
the  vertebral  border  of  the  scapula,  running  between  the  insertions  of  the  serratus 
magnus  and  rhomboidei  muscles  to  the  inferior  angle  of  the  seaimla,  where  it 
anastomoses  with  the  subscaimlar  artery.  In  its  course  it  gives  off  branches  to  the 
adjacent  muscles  and  anastomoses  with  the  supra-scapular  and  dorsalis  scapulte 
arteries. 

The  subclavian  or  supra-clavicular  triangle  (trigonum  omo-claviculare). — 
The  subclavian  triangle,  the  smaller  of  the  two  divisions  of  the  posterior  common 
triangle,  is  one  of  the  most  important  triangles  of  the  neck.  It  is  bounded  in 
front  by  the  posterior  border  of  the  sterno-mastoid  muscle  ;  above,  by  the  poste- 
rior belly  of  the  omo-hyoid  muscle ;  and  below,  by  the  clavicle.  The  base  of  the 
triangle,  formed  by  the  posterior  border  of  the  sterno-mastoid  muscle,  is  directed 
forward.  The  roof  of  this  triangle  is  formed  of  the  superficial  layer  of  the  deep 
fascia,  covered  by  the  platysma  myoides  muscle,  superficial  fascia,  and  skin.  The 
depth  of  this  space  is  increased  wdien  the  shoulder  is  raised  and  diniinislied  when 
it  is  depressed.  In  all  operations  in  this  triangle  the  shoulder  should  be  depressed, 
the  contents  of  the  triangle  being  thus  brought  nearer  to  the  surface.  Its  size  will 
depend  on  the  extent  of  the  attachment  of  the  trapezius  and  sterno-mastoid  muscles 
to  the  clavicle,  and  on  the  position  of  the  omodiyoid  muscle. 

Dissection. — The  roof  of  the  triangle  liaving  been  reflected  in  removing  the 
superficial  layer  of  the  deep  fascia,  some  lym]ihalic  glands,  loose  areolar  tissue, 
and  fat  will  Ije  seen  ;  a  small  jiortion  of  tlic  external  jugular  vein  is  also  visible  ; 
the  termination  of  the  transversalis  colli  and  supra-scai)ular  veins,  the  jugulo- 
cephalic  vein,   when  present,  and  some  additional  veins    from  the  muscles,  the 


60  SURGICAL  ANATOMY. 

layer  of  deep  fascia  (posterior  process)  covering  the  deeper  structures, — namely, 
the  scaleni  muscles,  the  phrenic  nerve,  the  cervical  trunks  of  the  axillary  or 
brachial  plexus  of  nerves, — and  the  subclavian,  supra-scapular,  and  transversalis 
colli  vessels  will  be  seen.  Remove  the  posterior  process  of  the  deep  fascia  iVom 
the  triangle  and  study  these  deeper  structures. 

Contents  of  the  Subclavian  Triangle. — Crossing  the  lower  part  of  the 
triangle  beneath  the  clavicle  are  tlie  siqna-scapular  artery  and  vein ;  these  vessels 
pass  in  front  of  the  third  ])ortion  of  the  subclavian  artery  (the  point  of  election),  and 
maj'  be  the  source  of  severe  hemorrhage  if  divided  when  ligating  the  artery.  The 
relation  of  the  supra-scapular  to  the  subclavian  artery  at  its  point  of  election  is  the 
same  as  that  held  by  the  middle  sterno-mastoid  artery  to  the  common  carotid  artery 
at  its  point  of  election.  Crossing  the  upper  angle  of  the  triangle  are  the  transversalis 
colli  artery  and  vein.  Entering  the  triangle  behind  the  jiosterior  Ijorder  of  the  lower 
part  of  the  sterno-mastoid  muscle  is  the  external  jugular  vein,  which  jiasses  in  front 
of  the  subclavian  artery  to  reach  the  subclavian  A-ein.  The  external  jugular  vein 
is  here  joined  bj^  the  supra-scapular  and  transversalis  colli  veins,  and  at  times  by 
a  small  branch  (jugulo-cephalic)  which  passes  over  the  clavicle,  connecting  the 
cephalic  with  the  external  jugular  vein.  The  supra-.scapular,  transversalis  colli, 
jugulo-cephalic,  posterior  external  jugular,  and  some  smaller  veins  at  times  form 
a  plexus  in  front  of  the  sul:)clavian  artery.  This  plexus  of  veins,  especially  when 
distended,  renders  operations  in  this  space  difficult.  Emerging  from  beneath  the 
posterior  border  of  the  sterno-mastoid  and  scalenus  anticus  muscles  is  the  third 
portion  of  the  subclavian  artery,  which  crosses  the  triangle  obliquely  downward  and 
outward.  The  subclavian  artery  rises  in  the  neck,  about  three-fourths  of  an  inch 
above  the  clavicle.  In  nearly  every  instance  it  runs  1>ehind  the  scalenus  anticus 
muscle,  but  it  may  pass  in  front  of  that  muscle  or  between  its  fibers.  Normally, 
the  third  part  of  the  subclavian  artery  does  not  give  off  any  branches ;  the  poste- 
rior scapular,  however,  one  of  the  terminal  branches  of  the  transversalis  colli  arterj'-, 
often  arises  from  this  portion  of  the  vessel ;  the  transversalis  colli  artery  itself,  or 
the  supra-scapular  artery,  may  arise  from  the  third  jwrtion  of  tlie  subclavian  artery. 
Tlie  .subclavian  vein  occupies  a  position  below  and  anterior  to  tlie  artt'ry,  not  being 
visible  frequently  in  a  dissection  of  the  subclavian  triangle.  It  lies  upon  the  first 
rib,  in  front  of  the  anterior  scalene  muscle,  and  bcliind  the  clavicle.  Passing 
downward  over  the  anterior  scalene  muscle,  beneath  the  posterior  process  of  the 
deep  fascia,  is  the  phrenic  nerve,  which  enters  the  chest  through  its  upper  opening, 
and  Ix'twecn  the  sul)clayian  artery  and  vein.  Iiuiniing  through  the  upper  and 
outer  part  of  the  triangle,  above  and  external  to  the  suliclavian  artery,  are  the  three 
cervical  trunks  of  the  axillary  or  brachial  plexus  of  nerves,  which  emerge  at  the  side 
of  the  neck  from  between  the  anterior  and  middle  scalene  muscles.     In  the  opera- 


DISSECTION  OF  THE  NECK.  61 

tion  of  ligation  of  tlie  tiiinl  jMH-tion  of  tlic  suliciaviaii  artery,  tlic  upper  trunk  of 
tlie  plexus  may  be  mistaken  fur  the  artery,  and  the  lii^^aluro  passed  around  it. 
This  trunk  is,  therefore,  a  \ery  useful  guide  in  locating  the  artery,  and  should 
ahvays  be  kept  in  mind.  X  few  lymphatic  glands,  which  arc  continuous  with  the 
axillary  lymphatics,  arc  found  in  this  space.  These  glands  should  always  be 
removed  in  the  radical  ojteration  for  removal  of  carcinoma  of  the  mannnary  gland. 
The  triangle  is  also  crossed  by  the  supra-scapular  and  posterior  thoracic  nerves 
and  the  nerve  to  the  subclavius  muscle. 

The  y?oor  of  the  trianylc  is  formed  by  the  scalenus  medius  and  posticus  muscles, 
the  first  rib,  and  the  upper  digitation  of  the  serratus  magnus  muscle. 

The  inferior  carotid  triangle  is  bounded  in  front  by  the  median  line  of  the 
neck;  behind,  l)y  the  anterior  l)order  of  the  stcrno-cleido-mastoid  muscle;  and 
above,  by  the  anterior  belly  of  the  omo-hyoid  muscle.  The  roof  is  formed  by  the 
skin,  the  superficial  fascia,  which  contains  the  platysma  myoides  muscle,  and  the 
descending  branch  of  the  superficial  cervical  nerve,  and  by  tlie  superficial  layer  of 
the  deep  fascia.  The'  outer  margins  of  the  sterno-hyoid  and  sterno-thyroid,  and 
the  anterior  margin  of  the  sterno-mastoid  muscle  cover  the  more  important  con- 
tents of  the  triangle,  and  should  be  drawn  aside  before  dissecting  the  deeper  struc- 
tures. 

Contents  of  the  Triangle. — The  common  carotid  artery  (not  strictly  in  the 
triangle,  as  the  vessels  lie  under  the  margin  of  the  sterno-mastoid  muscle,  but  so 
closely  related  to  the  contents  of  the  triangle  that  mention  of  it  here  is  proper),  the 
internal  jugular  vein,  and  the  pneumogastric  nerve,  all  three  inclosed  in  a  common 
.sheath,  in  front  of  which  are  tilaments  of  nerves  derived  from  the  loop  of  com- 
munication between  the  descendens  hypoglossi,  a  branch  of  tlie  hypo-glossal,  and 
the  communicantes  hypoglossi  ner^^es,  which  are  deep  branches  of  the  cervical 
plexus ;  behind  the  sheath  of  the  vessels  are  the  sympathetic  nerve  and  its  cardiac 
branches.  Upon  the  inner  side  of  the  sheath  of  the  vessels  are  the  lateral  lobe  of 
the  thyroid  gland,  the  trachea,  the  lars'^nx,  the  esophagus,  the  inferior  or  recurrent 
laryngeal  nerve  (motor  nerve  of  the  larynx),  which  occupies  the  groove  between 
the  trachea  and  the  esophagus,  and  the  terminal  portion  of  the  deep  chain  of 
cervical  lymjjhatic  glands.  To  the  outer  side  of  the  .sheath  of  the  vessels,  running 
over  the  scalenus  anticus  muscle,  is  the  phrenic  nerve.  The  inferior  thyroid 
artery,  a  branch  of  the  thyroid  axis,  passes  upward  and  inward  through  this  space 
to  the  outer  side  of  and  then  behind  the  sheath  of  the  vessels.  Situated  deeply  in 
the  interval  between  the  longus  colli  and  the  scalenus  anticus  muscle,  and  behind 
the  sheath  of  the  vessels,  are  the  vertebral  artery  and  its  accompanying  vein.  In 
this  triangle  the  relation  between  the  internal  jugular  vein  and  the  common 
carotid  artery-  differs  upon  the  two  sides  of  the  neck  ;  upon  the  right  side  the  vein 


62  SURGICAL  ANATOMY. 

is  a  little  to  the  outer  side  of  the  artery,  the  tAvo  vessels  being  in  the  lower  part  of 
the  triangle,  separated  by  a  narrow  interval,  while  on  the  left  side  it  lies  closer  to 
the  artery  and  somevyhat  overlaps  it. 

The  floor  of  tJie  triangle  is  formed  by  the  longus  colli  and  scalenus  anticus 
muscles. 

The  superior  carotid  triangle  is  bounded  above  by  the  posterior  belly  of  the 
digastric  muscle  ;  behind,  by  the  anterior  border  of  the  sterno-mastoid  muscle  ;  and 
below,  by  the  anterior  belly  of  the  omo-hyoid  muscle  ;  its  apex  is  directed  toward 
the  median  line  of  the  neck.  Its  roof  is  formed  by  the  skin,  the  superficial  fascia, 
the  platysma  mj'oides  muscle,  and  the  superficial  layer  of  the  deep  fascia. 

Contents  of  the  Superior  Carotid  Triangle. — These  are :  The  common 
carotid  artery  and  its  terminal  divisions, — the  external  and  the  internal  carotid, — 
the  internal  jugular  vein,  and  the  pneumogastric  nerve ;  these  are  all  inclosed 
in  a  common  sheath,  the  vein  lying  to  the  outer  side  of  the  artery  and  the 
nerve  between,  and  on  a  plane  posterior  to  both,  resembling  the  ramrod  in 
a  double-barreled  gun.  The  common  carotid  artery  usually  divides  into  the 
external  and  internal  carotid  arteries,  on  a  level  with  the  upper  border  of  the 
thyroid  cartilage ;  division  may,  however,  take  place  below  or  above  this  point. 
In  tliis  triangle  the  external  carotid  arteiy  gives  off  the  superior  thyroid, 
lingual,  facial,  occipital,  and  the  ascending  pharyngeal  artery,  all  of  which, 
excepting  the  occipital,  are  accompanied  by  their  corresponding  veins  on  their 
way  to  empty  into  the  internal  jugular  vein.  Passing  downward  in  front  of 
the  carotid  sheath  is  the  descendens  hypoglossi  nerve,  and  behind  the  sheath, 
the  sympathetic  nerve.  To  the  outer  side  of  the  sheath,  above,  is  the  spinal 
accessor}'  nerve,  wliicli  pierces  the  sterno-mastoid  muscle  ;  to  the  inner  side 
of  the  sheath  is  the  superior  laryngeal  nerve,  a  branch  of  the  pneumogastric, 
accompanied  by  the  superior  laryngeal  artery,  a  branch  of  the  superior  thyroid 
arterj'.  Both  the  superior  laryngeal  artery  and  the  internal  laryngeal  branch  of 
the  superior  laryngeal  nerve  enter  the  larynx  through  the  thyro-hyoid  mem- 
brane. To  the  inner  side  of  the  sheath  of  the  vessels,  and  a  little  lower,  the 
superior  thyroid  artery  and  the  external  laryngeal  nerve,  a  branch  of  the  superior 
laryngeal  nerve,  are  seen  passing  beneath  the  sterno-th3'roid  muscle.  The  hypo- 
glossal nerve  is  seen  in  the  upper  part  of  the  triangle,  curving  around  the  occipital 
artery  at  its  origin  from  the  external  carotid,  and  crossing  over  the  external 
and  internal  carotid  arteries.  ITpon  the  inner  side  of  the  triangle  are  the  upper 
part  of  the  larynx  and  the  lower  jinrtiim  of  the  idiarynx.  In  the  deep  jiart  of 
the  ti'iangle,  to  the  inner  side  of  the  slieath  of  the  vessels,  are  seen  the  pharynx, 
the  esophagus,  and  the  dee]>  cliain  of  the  cervical  lymphatic  glands,  the  terminal 
portion  of  which  iias  lieen  observed  when  dissecting  the  inferior  carotid  triangle. 


DISSECT/OX  OF  THE  NECK.  63 

The  ^miH'rior  carotid  is  the  triangle  of  clcdimi  for  the  liirutiou  of  the  eoninuui 
CiU'otid  urtery,  the  artery  being  more  superlicinl  ami  aeeessil)le  here.  Crossiii;;-  tlie 
sheath  of  tlie  vessels  in  this  tritingle  is  the  middle  sterno-mast(ud,  a  small  hraneh 
of  the  superior  thyroid  artery,  which  is  severed  in  the  ligation  of  the  common 
carotid  artery  in  this  triangle. 

The  floor  of  the  trlungle  is  formed  l)y  the  (hyro-hyoid  musele,  the  hyo-glossus 
muscle,  and  the  middle  and  inferior  constrictor  niuscles  of  the  pharynx. 

The  submaxillary  or  digastric  triangle,  the  uppermost  of  the  three  anterior 
triangles,  is  bounded  above  by  the  lower  border  of  the  body  of  the  lower  jaw,  and  a 
line  drawn  from  the  angle  of  the  lower  jaw  to  the  mastoid  process  of  the  temitoral 
bone;  below,  by  the  posterior  bellj^  of  the  digastric  and  the  stylo-hyoid  muscle, 
and  the  line  of  these  muscles  extended  to  the  median  liui-  of  the  neck  ;  and,  in 
front,  by  the  middle  line  of  the  neck.  Its  niuj  is  formed  by  the  skin,  the  super- 
ficial fascia,  the  platysma  myoides  muscle,  and  the  superficial  layer  of  the  deep 
fascia.  The  portion  of  the  deep  cervical  fascia  helping  to  form  the  roof  of  this 
triangle  is  verj'^  strong. 

Contents  of  the  Subjiaxillary  Triangle. — The  .stylo-maxillary  ligament,  a 
process  of  the  deep  cervical  fascia  which  extends  from  the  styloid  ])rocess  of  the 
temporal  bone  to  the  angle  of  the  lower  jaw  and  separates  the  submaxillary  and 
parotid  salivary  glands,  divides  the  submaxillar}'  or  digastric  triangle  into  two 
portions,  an  anterior  and  a  posterior.  The  posterior  jjortion  contains  a  part  of  the 
external  carotid  artery,  embedded  in  the  substance  of  the  parotid  gland,  the  internal 
carotid  artery,  the  internal  jugular  vein,  the  i)neumogastric,  glosso-pharyngeal, 
hypo-glossal,  and  sympathetic  nerves,  the  origins  of  the  stylo-glossus  and  stylo- 
pharj'ngeus  muscles,  and  the  stylo-hyoid  ligament.  The  last  three  of  these  struc- 
tures, with  the  glosso-pharyngeal  nerve,  pass  into  the  anterior  part  of  the  triangle 
between  the  internal  and  external  carotid  arteries.  In  addition  to  the  terminal 
portion  of  the  stylo-pharyngeus  and  stylo-glossus  muscles  the  anterior  portion 
contains  the  stylo-hyoid  ligament  and  the  glosso-pharyngeal  nerve,  which  pass 
from  the  posterior  portion,  the  submaxillary  gland,  tlie  facial  artery  and  vein,  the 
ascending  palatine,  tonsillar,  submaxillary,  and  submental  branches  of  the  facial 
artery,  all  of  which  arise  within  the  triangle,  the  hypo-glossal  neiwe,  the  mylo- 
hyoid nerve,  the  raylo-hyoid  arter\',  and  lymphatic  glands.  A  chain  of  lymphatic 
glands,  ten  to  fifteen  in  number,  is  found  below  the  body  of  the  lower  jaw.  These 
glands  belong  to  the  superficial  cervical  lymphatics,  and  are  known  as  the  sub- 
maxillary lymphatic  glands.  In  malignant  growths  of  tlie  li]),  lower  jaw,  tongue,  or 
oral  and  pharj'ngeal  mucous  membrane,  this  chain  of  glands  will  soon  become 
infected  and  should  always  be  removed,  whether  enlarged  or  not.  In  the  opera- 
tion for  the  removal  of  a  malignant  growth  involving  the  areas  whicli  these  glands 


64  SURGICAL  ANATOMY. 

di-ain,  the  first  step  should  consist  in  the  removal  of  the  submaxillary  lymphatic 
glands  of  both  sides  of  the  neck,  and,  in  some  instances,  of  the  submaxillary 
salivary  gland  ;  the  final  step  consists  of  the  removal  of  the  growth.  Tuberculosis 
of  these  glands  is  a  not  uncommon  condition,  because  of  the  large  area  from  which 
they  receive  lymph  ;  infection  from  inflammatory  affections  of  the  pharyngeal, 
nasal,  and  oral  mucous  membranes,  as  well  as  from  carious  teeth,  is  very  frequently 
the  cause  of  disease  of  these  glands.  An  extensive  cervical  cellulitis,  known  as 
Ludwig's  angina,  may  originate  from  septic  processes  in  the  submaxillary  lym- 
phatic glands. 

The  floor  of  the  submaxillary  triangle  is  formed  by  the  mylo-hyoid  muscle,  the 
anterior  belly  of  the  digastric,  the  hyo-glossus,  the  superior  constrictor,  and  a 
small  portion  of  the  middle  constrictor  muscle  of  the  pharj-nx. 

Dissection. — The  roof  of  the  triangle  having  been  reflected  in  removing  the 
superficial  layer  of  the  deep  cervical  fascia,  the  submaxillary  salivary  gland,  with 
the  exception  of  its  upper  j^ortion,  which  is  hidden  by  the  body  of  the  lower  jaw, 
will  now  be  seen.  The  gland  is  surrounded  by  a  fibrous  capsule,  which  is  derived 
from  the  superficial  layer  of  the  deep  fascia.  Displace  the  submaxillary  gland  up- 
ward upon  the  face,  holding  it  tliere  Avith  hooks  while  further  dissection  of  the 
triangle  is  made.  In  displacing  the  gland  avoid  severing  the  facial  vein,  which  passes 
over  it,  and  the  facial  artery,  which  passes  through  the  groove  on  its  deep  surfaces. 

The  lingual  triangle. — The  portion  of  the  submaxillary  or  digastric  triangle, 
through  which  the  lingual  artery  runs,  is  frequently  spoken  of  as  the  lingual 
triangle.  In  relation  with  the  triangle  are  the  submaxillary  gland,  the  posterior 
belly  and  the  tendon  of  the  digastric  muscle,  the  hypo-glossal  nerve,  the  hyo- 
glossus  muscle,  and  the  middle  constrictor  muscle  of  the  pharynx.  This  sub- 
division of  the  submaxillary  triangle  is  bounded  above  by  the  hypo-glossal  nerve, 
posteriorly  by  the  posterior  belly  of  the  digastric  muscle,  and  anteriorly  by  the 
mylo-hyoid  muscle  ;  its  rooj  is  formed  by  the  submaxillary  gland,  and  its  floor 
by  the  hyo-glossus  and  middle  constrictor  muscle  of  the  pharynx.  In  ligating 
the  lingual  artery  an  incision  is  carried  above  and  parallel  with  the  greater  cornu 
of  the  hyoid  hoxiQ ;  the  skin,  the  superfic'ial  fascia,  the  platysma  myoides  muscle, 
and  the  superficial  layer  of  the  deep  fascia  are  divided,  and  the  submaxillary 
gland  is  expo.sed.  The  gland  is  lifted  upward,  when  the  artery  will  be  found 
beneath  the  hyo-glossus  muscle  and  beneath  the  interval  between  the  hypo-glossal 
nerve  and  the  tendon  of  the  digastric  muscle.  In  making  the  incision  through 
the  hyo-glossus  muscle  care  must  be  observed  to  avoid  wounding  the  middle 
constrictor  muscle,  division  of  which  would  open  the  pharynx.  It  is  not  necessary 
to  cut  the  hyo-glossus,  as  the  artery  is  readily  secured  before  it  passes  beneath  that 
muscle  without  endangering  the  pharj'nx. 


DISSECrtOX  OF  THE  NECK.  65 

Dissection. — Divide  the  .stenio-inastoid  muscle  at  about  its  mitldle,  and  reflect 
the  two  portions.  This  exposes  the  descendens  hypoglossi  nerve,  wliidi  lies  niKin 
the  sheath  of  tlie  vessels,  the  comnninicnntes  hypoglossi  nerves,  the  ansa  hypoglossi, 
the  tendon  of  the  oino-hyoid  muscle,  the  sheath  of  the  vessels,  the  spinal  accessory 
nerve,  the  phrenic  nerve,  the  cervical  plexus,  the  anterior  scalene  muscle,  and  a 
portion  of  the  subclavian  vessels  and  some  of  their  branches.  The  sj)inal  acces- 
sory and  phrenic  nerves,  the  cervical  plexus,  the  anterior  scalene  muscle,  and  the 
subclavian  vessels  are  covered  by  the  posterior  portion  of  the  two  ])r<>cesses  of  the 
deep  cervical  fascia  (prevertebral),  overlaid  by  some  areolar  and  fatty  tissue.  Re- 
move the  fat  and  areolar  tissue  with  the  layer  of  fascia  (prevertebral)  covering 
the  structures  just  named,  inferior  thyroid,  and  the  vertebral  .supra-.scapular, 
transversalis  colli,  and  vertebral  arteries. 


THE    CERVICAL   PLEXUS   OF   NERVES. 

The  cer\acal  plexus  is  formed  by  the  anterior  branches  of  tlie  upper  four  cer- 
vical nerves.  It  is  situated  in  the  upper  part  of  the  neck,  beneath  the  stcrno- 
mastoid  muscle,  and  rests  upon  the  scalenus  medivis  and  levator  anguli  scapulse 
muscles.  It  differs  from  the  axillary  or  brachial  plexus  in  resembling  a  network 
rather  than  a  bumlle  of  cords.  Each  nerve,  excepting  tlie  first,  divides  into  an 
ascending  and  a  descending  branch  ;  these  unite  with  similar  parts  of  the  contigu- 
ous nerves,  thus  forming  a  plexus.  The  branches  of  the  plexus  are  divided  into 
a  superficial  and  a  deep  set ;  the  superficial  set  of  branches  has  been  described 
with  the  superficial  fascia  of  the  neck.  The  deep  set  of  branches  is,  for  conveni- 
ence, divided  into  an  internal  and  an  external  series.  The  internal  series  includes 
the  phrenic,  communicantes  hypoglossi,  muscular,  and  communicating  branches; 
the  external  series  includes  muscular  and  communicating  branches. 

The  phrenic  nerve,  the  internal  respiratory  nerv-e  of  Bell,  sujjplies  the 
diaphragm.  It  arises  from  the  third  and  fourth  cervical  ner^^es,  and  receives  a 
communicating  branch  from  the  fifth.  It  passes  downward  and  inward  over  the 
anterior  surface  of  the  anterior  scalene  muscle,  beneath  the  omo-hyoid  muscle,  the 
transversalis  colli  and  supra-scapular  arteries,  and  the  thoracic  duct  (left  side),  and 
enters  the  upper  opening  of  the  chest  behind  the  subclavian  vein,  and  in  front  of 
the  subclavian  arterA-.  It  then  crosses  in  front  of  the  internal  mammary  artery, 
irom  without  inward,  and  the  root  of  the  lung,  and  pa.sses  through  the  middle 
mediastinum  between  the  mediastinal  layer  of  the  pleura  and  the  pericardium,  to 
reach  the  diaphragm,  which  it  pierces  for  final  di.stribution  upon  its  lower  surface. 
At  the  lower  part  of  the  neck  it  is  joined  by  a  filament  of  the  sympathetic  nerve, 
and  at  times  by  a  branch  from  the  nerve  to  the  subclavius  muscle.     In  the  chest  it 

S—  II -T 


66  SURGICAL  ANATOMY. 

is  accompanied  by  the  arteria  comes  nervi  plirenici,  a  branch  of  the  internal  mam- 
mary artery.  The  origin  of  the  phrenic  nerve  is  mainly  from  the  fourtli  cervical 
segment  of  the  spinal  cord,  which  is  situated  behind  the  upper  part  of  the  body  of 
the  fourth  cervical  vertebra,  and  the  fact  that  this  nerve  is  the  one  which  innervates 
the  diaphragm,  explains  the  fatality  due  to  injury  of  the  spinal  cord  through 
fractures  and  dislocations  of  the  upper  cervical  vertebrae. 

The  communicantes  hypoglossi  (communicantes  noni)  arise  from  the  second 
and  third  cervical  nerves,  pass  downward  to  the  outer  side  of  the  internal  jugular 
vein,  then  cross  in  front  of  the  vein,  and  join  the  descendens  hypoglossi,  a  branch 
of  the  hypo-glossal  nerve,  in  front  of  the  sheath  of  the  blood  vessels,  forming  the 
loop  known  as  the  ansa  hypoglossi.  Tlie  descendens  and  communicantes  hypoglossi 
supply  the  depressor  muscles  of  the  hyoid  bone  and  larynx — namely,  the  sterno- 
hyoid, sterno-thyroid,  and  omo-hyoid  muscles.  This  loop  (ansa)  may  be  behind 
the  internal  jugular  vein,  and  within  or  outside  the  sheath  of  the  vessels. 

The  muscular  branches  of  the  internal  series  arise  from  the  first,  second, 
third,  and  fourth  cervical  nerves ;  they  supply  the  rectus  capitis  anticus  major  and 
minor,  rectus  lateralis,  and  longus  colli  muscles. 

The  communicating  branches  of  the  internal  series  connect  the  cervical  plexus 
with  the  sympathetic,  jmeumogastric,  and  hj'po-glossal  nerves. 

The  muscular  branches  of  the  external  series  supply  the  sterno-mastoid, 
the  trapezius,  the  levator  anguli  scapula?,  and  the  scalenus  medius  muscle ;  the 
branch  to  the  sterno-mastoid  muscle  arises  from  the  second  cervical  nerve  ;  the 
branches  to  the  levator  anguli  scapulte,  trapezius,  and  scalenus  medius  muscles  from 
the  third  and  fourth  cervical  nerves. 

The  communicating  branches  of  the  external  series  connect  the  cervical  plexus 
with  the  spinal  accessory  nerve  in  the  sterno-mastoid  muscle,  in  the  occipital  triangle, 
and  lastly  beneath  the  trapezius  muscle,  forming  the  subtrapezial  plexus. 

Pain  in  one  or  more  of  the  areas  supplied  by  the  various  sensory  branches'of 
the  cervical  nerves  may  be  caused  by  caries  of  the  cerAdcal  vertebroe.  Irritation  of 
these  nerves  produces  pain  or  spasm  of  the  muscles  in  the  regions  supplied  by  the 
posterior  branches  of  the  nerves,  as  well  as  in  those  supplied  by  the  cervical  and 
brachial  plexuses.  ' 


Next  examine  the  carotid  sheath  and  the  .structures  in  relation  with  it. 

Tlie  Carotid  Sheath  is  formed  by  the  division  of  the  superficial  layer  of  the 
deep  cervical  fascia  whicli  jiasses  beneath  the  sterno-mastoid  muscle,  by  the  jire- 
vertebral  and  ]>r( •tracheal  fascia\     It  is  diviiled  by  sei)ta  into  three  compartments: 


PLATE  XII 


External  carotid  a.  First  portion  of  lingual  a. 


Inferior  dental  n 
Facial  n. 


Spinal  accessory  n 
anterior  to  sterno-mastoid  in 


Internal  carotid  a 

Spinal  accessory  n.  posterior  to  sterno 
mastoid  m.  and  superficial  branches  of  ^ 

cervical  plexus-     - 


Inferior  thyroid  a.  at 
origin  and  vertebral  a. 


Brachial  plexus -/- 


3d  portion  of  subclavian  a 


Facial  a. 

Second  portion  of  lingual  a. 


Superior  thyroid  a. 


Common  carotid  a,  in 
superior  carotid  triangle 


Common  carotid  a.  in 
inferior  carotid  triangle 


Innominate  a. 


LINES  OF  INCISION  FOR  EXPOSURE  OF  ARTERIES  AND  NERVES. 
67 


PLATE  XIV, 


Temporal  v, 
Posterior  auricular  artery  and  nerve 
Posterior  auricular  v. 


Internal  maxillary  v, 
External  carotid  a. 

Superior  sterno-mastold  a. 
Occipital  a. 

Ascending  pharyngeal  a. 
Facial  a. 
Facial  V. 


Suporficlat  cervical  a/ 


Posterior  scapular 
Superficial  cervical  v 
Posterior  scapular 

Transversalls  coll 

Transversalis  colli  a 
Subclavi::n  a  (3d  portion) 
Suprascapular 


Communicating  v. 
Anterior  jugular  v. 
Bifurcation  of  innominate  a. 
Subclavian  a. (1st  portion) 
Vtriebral  a. 
Inferior  sterno-mast'iJ  a. 
Subclavian  v. 
Suprascapular  ^ 


VESSELS  AND 


NERVES  OE   NECK, 
70 


PLATE  XV. 


Posterio    auricular  artery  end  nerve 
Sterno-mastoid  m. 
Splenius  ccpitis  m 
Complex.us  m. 


Facial  n, 

Norve  to  stylo-liyoid  m.and  posttirior  bolly  of  digastric  m. 
Posterior  belly  of  digastric  rr., 
Stylo-hyoid  m. 

Superior  constrictor  m.of  pharynx 
Middle  constrictor  m.of  pharynx 
Whartor's  duct 
Hyoglossus  m. 


Posterior  thoracic  n. 
Posterior  belly  of  omo-hyoid  mf 
Serralus  magnus  m' 
Scalenus  medlus  m. 
Suprascapular  n.' 

Brachial  plexus  of  nerves' 

Lower  trunk  of  brachial  plexus 
Upper  trunk  of  brachial  plexus 
Middle  trurlt  of  brachial  plexus 

Ant-div.7th  cervical  n. 


no-mastoid  m. 
Recurrent  iaryngoal  n. 
Sterno-mastoid  m. 
Scalenus  anticus  m. 
Anl.div.6th  cervical  n. 


MUSCLES  AND  NERVES  OF  NECK. 
71 


DISSECTIOX  OF  Tin-:  XECK.  73 

the  inner  contains  the  common  carotid  artery,  the  outer  the  inteiiial  jugular 
vein,  and  tlie  posterior  tlie  piicuniogastrie  nerve. 

Tlie  descendens  hypoglossi  nerve  (descendens  noni)  is  usually  seen  lying  in 
front  of  the  carotid  sheath,  Init  occasionally  it  lies  within  the  anterior  wall  of  the 
sheath.  It  is  given  off  from  the  liypo-glossal  nerve  as  the  latter  Avinds  around  the 
occipital  artery.  It  is  not  a  truu  hranch  of  the  hypo-glossal  nerve,  its  fibers  origi- 
nally arising  from  the  cervical  plexus  and  running  with  the  trunk  of  the  hyj)o- 
glossal  nerve  for  a  shoi't  distance.  It  eonnnunicates  with  the  communicantes 
hypoglossi,  deep  branches  of  the  cervical  plexus,  thus  forming  a  loop  known  as  the 
ansa  hyjioglossi,  which  supplies  the  sterno-hyoid,  sterno-thyroid,  and  both  bellies  of 
the  omo-hyoid  muscle. 

Lymphatic  glands. — In  relation  with  tlie  outer  wall  of  the  sheath  of  the 
vessels,  observe  the  deep  chain  of  lymphatic  glands;  these  glands  arc  in  commu- 
nication with  the  superficial  chain,  and  therefore  in  enlargement  of  the  latter  the 
deep  chain  is  more  or  less  involved.  Every  surgeon  who  has  had  experience  in 
the  removal  of-  glandular  tumors  of  the  neck  appreciates  this  fact  when  forced  to 
carry  the  dissection  to  the  extent  of  exposing  the  carotid  sheath  for  some  distance 
if  he  Avould  remove  all  enlarged  glands.  In  cases  where  it  is  not  possible  to  make 
a  good  exposure  and  dissect  Avith  safety  around  the  vessels  by  simply  displacing 
the  sterno-mastoid  muscle,  it  will  be  necessary  to  divide  the  muscle.  In  making  a 
difficult  dissection  in  a  region  rich  in  important  structures  success  is  obtained  only 
by  having  a  good  exposure,  which  necessitates  a  large  wound. 

Dissection. — Remove  the  deep  chain  of  lymphatic  glands  together  with  the 
fat  and  connective  tissue  around  them,  and  lay  ojjen  the  sheath,  when  the  carotid 
artery,  the  internal  jugular  vein,  and  the  pneumogastric  nerve  will  l)e  brought  into 
view.  The  internal  jugular  vein  lies  to  the  outer  side  of  the  common  carotid 
artery,  while  the  pneumogastric  nerve  lies  between  the  vein  and  artery  in  a  jdane 
posterior  to  both. 

The  internal  jugular  vein  is  the  continuation  of  the  lateral  sinus,  and  begins 
at  the  jugular  foramen,  where  that  .sinus  is  joined  by  the  inferior  petrosal  sinus. 
The  vein  is  somewhat  dilated  at  it  origin,  this  enlargement  constituting  the 
so-called  bulb  or  sinus,  which  lies  in  the  jugular  fos.sa.  At  the  jugular  foramen 
the  vein  lies  behind  and  external  to  the  glosso-pharyngeal,  pneumogastric,  and 
spinal  accessor^'  nen^es.  It  jiasses  down  the  side  of  the  neck,  at  fir.st  beneath 
and  external  to  tlie  internal  carotid  artery,  then  on  the  outer  side  of  the  internal 
carotid,  and,  finally,  on  the  outer  side  of  the  common  carotid  artery.  It  terminates 
by  joining  tlie  subclavian  vein  just  external  to  the  upper  margin  of  the  sterno- 
clavicular articulation  to  form  the  innominate  vein.  It  occupies  the  outer  com- 
partment of  the  carotid  sheath,  and  is  separated  from  the  common  carotid  artery 


74  SURGICAL  ANATOMY. 

and  pneumogastric  nerve  by  septa.  At  the  lower  part  of  the  iieek  the  internal 
jugular  veins  observe  a  slightly  different  course.  At  its  termination  the  right 
internal  jugular  vein  leaves  the  right  common  carotid  artery  to  join  the  subclavian 
vein,  forming  a  triangular  interval  between  the  artery  and  vein,  while  the  left 
internal  jugular  vein  turns  forward  to  join  the  subclavian  vein,  and  overlaps  the 
left  common  carotid  artery  at  the  root  of  the  neck.  The  internal  jugular  vein  has 
a  pair  of  valves  about  three-fourths  of  an  inch  from  its  termination.  Opposite  the 
angle  of  the  lower  jaw  a  communicating  branch  from  the  external  jugular  vein 
and  some  pharyngeal  veins  empty  into  it.  Near  the  level  of  the  greater  cornu 
of  the  hyoid  bone  it  receives  the  facial  and  lingual  veins ;  lower,  the  superior 
thyroid  vein  ;  and  opposite  the  cricoid  cartilage,  the  middle  thyroid  vein. 

The  common  carotid  artery. — The  right  and  left  common  carotid  arteries 
are  dissimilar  in  origin,  but  occupy  similar  positions  in  the  neck  (for  this  reason 
but  one  artery  will  be  descriljed).  The  right  common  carotid  arises  from  the 
innominate  artery  behind  the  ujjper  margin  of  the  right  sterno-clavicular  articula- 
tion ;  the  left  common  carotid  arises  from  the  highest  part  of  the  transverse  portion 
of  the  arch  of  the  aorta.  As  the  left  common  carotid  artery  arises  within  the  chest, 
it  is  the  longer  of  the  two  vessels ;  it  may  be  divided  into  a  thoracic  and  a  cervical 
portion.  The  thoracic  portion  of  the  left  common  carotid  artery  will  be  described 
with  the  chest. 

The  course  of  the  common  carotid,  external  carotid,  and  internal  carotid 
arteries  when  the  face  is  turned  slightly  to  the  opposite  side,  is  represented  by  a 
line  drawn  from  the  sterno-clavicular  articulation  to  a  point  midwaj'  between  the 
angle  of  the  lower  jaw  and  the  mastoid  process  of  the  temporal  bone.  That  por- 
tion of  the  line  below  the  level  of  the  greater  cornu  of  the  hyoid  boire  indicates 
the  course  of  the  common  carotid  artery,  and  that  part  above  the  hyoid  bone  indi- 
cates the  position  of  the  internal  carotid  and  external  carotid  arteries.  The 
external  carotid  deviates  slightly  from  this  line  toward  the  angle  of  the  lower  jaw. 

At  the  lower  part  of  the  neck  the  common  carotid  artery  is  situated  deeply 
beneath  the  sternal  origin  of  the  sterno-cleido-mastoid,  the  stcrno-hyoid,  and  the 
sterno-thyroid  muscle,  being  separated  from  its  fellow  by  the  trachea,  which  is 
about  an  inch  in  width.  Thence  it  ascends  in  the  inner  compartment  of  the 
sheath  of  the  vessels,  beneath  the  anterior  border  of  the  sterno-cleido-mastoid 
muscle,  to  terminate  opposite  the  upper  border  of  the  thyroid  cartilage  by  bifurcat- 
ing into  tiie  external  and  internal  carotid  arteries.  As  the  artery  ascends  it 
diverges  from  the  median  line,  on  account  of  the  interposition  of  the  lateral  lobe 
of  the  thyroid  gland  between  it  and  the  trachea,  and  as  a  result  of  the  width  of  the 
larynx.  It  is  covered  by  the  skin,  superficial  fascia,  platysma  myoides  muscle, 
superficial  layer  of  the  deep  fascia,  the  anterior  border  of  the  sterno-mastoid  mus- 


DISSECTION  OF  TIIK  NECK.  75 

cle,  and  the  anterior  wall  of  the  carotid  sheath  ;  in  addition  to  these,  at  the  lower 
part  of  the  neck  are  the  sterno-hyoid  and  sterno-thyroid  muscles,  the  thyroid  gland, 
which  slightly  overlaps  it,  the  omo-hyoid  muscle  and  the  anterior  jugular  vein, 
which  cross  it.  The  descendens  hypoglossi  nerve  and  ansa  hypoglossi  also  lie  in 
front  of  it,  and  the  middle  sterno-mastoid  artery  and  the  superior  and  middle 
thyroid  veins  cross  it.  Behind  it  are  the  rectus  capitis  anticus  major  and  tlie  longus 
colli  muscle,  the  pneumogastric,  sympathetic,  and  cardiac  nerves,  the  recurrent 
laryngeal  nerve,  at  the  lower  part  of  the  neck,  and  the  inferior  thyroid  artery 
crossing  behind  it  at  the  level  of  the  cricoid  cartilage.  To  the  inner  side  of  the 
artery  are  the  trachea  and  esophagus,  the  recurrent  laryngeal  nerve  lying  between 
them,  the  lateral  lobe  of  the  thyroid  gland,  the  terminal  portion  of  the  infei'ior 
thyroid  arterj',  the  larynx,  the  pharynx,  and  the  superior  thyroid  artery.  To  the 
outer  side  of  the  artery  are  the  internal  jugular  vein  and  the  pneumogastric  nerve. 

The  common  carotid  artery  seldom  gives  off  branches,  but  may,  when  the 
bifurcation  is  higher  than  usual,  give  off  the  .superior  tln'roid  artery.  The  bifur- 
cation of  the  artery  may  occur  higher  or  lower  than  the  upper  border  of  the 
thyroid  cartilage,  and  is  not  infrequently  situated  opposite  the  greater  cornu  of 
the  hyoid  bone. 

Aneurysm  of  the  common  carotid  artery  most  frequently  develojis  near  its 
bifurcation.  Pressure  upon  the  internal  jugular  vein  by  an  aneurysm  of  the 
common  carotid  artery  produces  cyanosis  or  duskiness  of  the  face  and  scalp,  head- 
ache, and  puffiness  or  edema  of  the  face  ;  pressure  upon  the  sympathetic  cord  causes 
dilatation  of  the  pupil,  and,  later,  contraction  of  the  pu])il  ;  ])r(•^^sure  upon  the 
superior  laryngeal  nerve  causes  cough,  and  spasm  or  paralysis  of  one  crico-thyroid 
muscle ;  and  pressure  upon  the  recurrent  laryngeal  nerve,  spasm  or  paralysis  of 
the  muscles  of  one  side  of  the  larynx,  hoarseness,  and  difficulty  in  phonation. 
These  aneurysms  at  the  side  of  the  neck  produce  a  pulsating  swelling  which 
resembles  that  seen  in  enlargement  of  one  lateral  lobe  of  the  thyroid  gland.  As 
the  thyroid  gland  adheres  to  the  trachea,  enlargements  or  tumors  of  that  organ 
move  upward  and  downward  with  the  larynx  and  trachea  during  deglutition, 
whereas  an  aneurysm  of  the  common  carotid  artery  remains  stationary. 

Ligation  of  the  common  carotid  artery. — In  wounds  or  aneurysm  of  this 
artery  or  one  of  its  branches,  it  may  require  a  ligature.  It  is  tied,  preferably,  in 
the  superior  carotid  triangle,  opposite  the  cricoid  cartilage  and  innnediately  above 
the  point  where  the  omo-hyoid  muscle  crosses  its  sheath.  The  incision  is  made 
along  the  anterior  border  of  the  sterno-mastoid  muscle,  cutting  through  the  skin, 
superficial  fascia,  platysma  myoides  muscle,  and  superficial  layer  of  the  deep  fascia  ; 
the  sterno-mastoid  muscle  is  then  displaced  outward,  and  the  sheath  with  the  descen- 
dens hypoglossi  nerv^e  upon   it  exposed.     As  the  internal  jugular  vein  slightly 


76  SURGICAL  ANATOMY. 

overlaps  the  outer  side  of  the  artery,  a  small  incision  should  be  made  in  the  inner 
side  of  the  sheath,  and  the  needle  passed  from  without  inward,  avoiding  the  inter- 
nal jugular  vein  and  the  pneumogastric  nerve.  The  opening  in  the  sheath  should 
lie  small,  so  that  the  vasa  vasorum  and  the  nutrition  of  the  vessel  will  not  be 
unnecessarily  disturbed.  In  exposing  the  carotid  sheath,  the  superior  or  middle 
thyroid  vein  and  the  middle  sterno-mastoid  artery  may  be  severed.  In  the  inferior 
carotid  triangle  the  artery  is  ligatured  with  more  difhculty  and  danger,  because  it 
is  deeper  and  covered  by  three  layers  of  muscles  :  the  sterno-thyroid,  sterno-hyoid, 
and  sterno-mastoid  ;  and,  on  the  left  side,  the  internal  jugular  vein  turns  forward 
in  front  of  the  artery  at  the  root  of  the  neck  to  join  the  subclavian  vein. 

Intercarotid  body  or  ganglion. — This  small,  oval,  reddish-brown  body  is 
situated  in  the  interval  between  the  external  and  internal  carotid-  arteries,  beliind 
the  bifurcation  of  the  common  carotid  artery.  It  receives  filaments  from  the 
sympathetic  nerve,  and  resembles  the  coccygeal  body  or  Luschka's  gland. 

The  Pneumogastric  or  Vagus  Nerve. — The  pneumogastric  nerve,  the  tenth 
and  longest  of  the  cranial  nerves,  has  an  extensive  area  of  distribution.  It  supplies 
branches  to  the  dura  mater,  external  ear,  pharynx,  larynx,  esophagus,  trachea, 
Ijronchi,  lungs,  stomach,  spleen,  liver,  and  to  the  sympathetic  system  of  nerves  in 
the  cervical,  thoracic,  and  abdominal  regions.  It  leaves  the  cranial  cavity  at  the 
jugular  foramen,  inclosed  within  the  same  sheath  of  the  dura  mater  as  the  spinal 
accessory  nerve.  It  runs  downward  between  the  internal  jugular  vein  and  the 
internal  carotid  artery,  passing  next  between  the  internal  jugular  A^ein  and  the 
common  carotid  artery,  lying  behind  and  between  them  in  the  posterior  com- 
partment of  their  sheath.  It  enters  the  chest  at  its  superior  opening.  On  the 
right  side  it  passes  between  the  first  portion  of  the  subclavian  artery  and  the 
subclavian  vein,  while  on  the  left  side  it  runs  between  the  first  portion  of  the 
subclavian  artery  and  the  common  carotid  artery,  beneath  the  left  innominate 
vein.  Its  course  in  the  chest  will  be  included  in  the  description  of  that  part  of  the 
body.  The  pneumogastric  nerve,  owing  to  its  position  between  the  internal 
jugular  vein  and  the  internal  carotid  artery,  is  closely  associated  with  the  glosso- 
pharyngeal, spinal  accessory,  and  hyjio-glossal  nerves.  These  nerves  accompany 
the  internal  carotid  artery  but  a  sliort  distance,  the  glosso-pharj'ngeal  nerve 
curving  forward  between  the  external  and  internal  carotid  arteries,  the  spinal 
accessory  nerve  turning  backward  beneath  the  internal  jugular  vein,  and  the 
hypo-glossal  nerve  curving  forward  over  the  internal  and  external  carotid  arteries 
and  the  root  of  the  occipital  arterj-. 

There  are  two  ganglia  on  the  pneumogastric  nerve  :  the  ganglion  of  the  root, 
and  the  ganglion  of  the  trunk.  The  ganglion  of  the  root  is  a  small,  rounded  swelling 
seen  upon  the  nerve  as  it  lies  in  the  jugular  foramen.     The  ganglion  of  the  trunk 


PLATE  XVI. 


Posterior  auricular  n. 
Facial  n. 

Transverse  process  of  atlas 
External  carotid  a. 

Ascending  pharyngeal  a. 
Lingual  n, 


Submaxillary  ganglion 
Hyo-glossus  m. 
Facial  a. 

Genio-hyo-glossus   m. 
Sublingual  a. 

Genio-hyoid  m. 

Left  d'gastric  m. 


Mylo-hyoid  nn.(cut) 


Occipital  a.--' 
Superior  sterno-mastoiu  a 


Descendens  hypoglossi  n 

Internal  catotid  a, 
Ant.div.4th  cervical  n 


Rectus  capitis  anticus  major 

Middle  sterno-mastoid  a, 


Subclavian  a, 


Subclavian  v. 
Suprascapular  a 
Inferior  stvrno-mastoid  a. 
InterneJ  nnammary  a. {under  phrenic  n.) 

Vertebral  v 
Bifurcation  of  innominate    a. 


Left  sterno-mastoid  m. 
Left  sterno-hyoid  and  sterno-thyroid  m. 
Inferior  thyroid  veins 
Sterno-thyroid  m. 
Sterno-hyuid  m. 
Sterno-rtlastoid   m. 


DEEP  STRUCTURES  OF  NECK-CAROTID  ARTERIES 

78  ■ 


^0  PNEUMOGASTRIC  NERVE. 


PLATE  XVI  i 


OSterno-mastoid  in 
Posterior  auricular  n 
Posterior  auricula'  a. 
Princeps  cervicis  a 
Occipital  a 


Great  occipital  n 
Occipitalis  m 


Fcitcrlor  belly  digastric  m.(cut) 
Facial  n. 
Stylo-hyoid  nn.(cut) 
tntornal  carotid  a. 
Ascending  pharyngeal  a. 
Stylo-pharyngous  m. 
Glcsco-phaiyngeal  n. 
Asconcling  palatine  a. 
Superior  constrictor  m. 
Tonsillar  a. 


Stylo-glossus  m. 
Facial  a. 

Senio-hyo-glossus  m. 

Genio-hyoid  rn. 

Left  digastric  m. 
(anterior  belly) 


Splenius  m 
Trapezius  nn.' 
Tracheio  mastoid  m 


Spinal  accessory  n 
Superior  cervical  synnp.gang 

Pneunfiogastric  nr 
Superior  laryngeal  n 

Middle  constrictor  m. 
Stylo-hyoid  ligament 

Internal  laryngeal  n. 

External  laryngeal  n. 

Rectus  capitis  anticus  major  m 

Cardiac  n. 

Sympathetic  n.- 
Scalenus  anticus  m. 

Ascending  cervical. a 


'liJdIe  cervical  symp,  gang 
Aitt.div.  8th. cervical  n 

Superior  intercostal  a, 

Subclavian  a.' 
Suprascapular  a 
Subclavian 


Sublingual  a. 

Hyo-glossus  m.(cut) 
Mylo-hyoid  m. 

Dorsalis  linguae  a. 
Hypoglossal  n. 

Lingual  a. 


Thyro-hyoid  membrane 
nferlor  constrictor  m. 

Thyroid  cartilage 

Crico-thyroid  m. 

Cricoid  cartilage 

Recurrent  laryngeal  n. 

Thyroid  axis  (a.) 
Vertebral  a. 

Pneumogastric  n. 


Ant.  div.  I  St. thoracic  n 

Phrenic  n 


Vertebral  v.  triferior  thyroid  vein* 

Internal  mammary  a. (under  phrenic  n.) 


SYMPATHETIC  NERVE  AND  LARYNGEAL  NERVES. 
79 


DISSECTION  OF  THE  NECK.  81 

is  a  long,  fusiform  enlargement,  situated  upon  tlie  nerve  ahout  one-half  of  an 
ineh  bi'low  the  jugular  foramen.  It  is  closely  associated  witli  tlie  hypo-glossal 
nerve,  Avhich  winds  around  its  outer  side ;  below  this  ganglion  the  vagus  receives 
some  fibers  from  the  accessory  portion  of  the  spinal  accessory  nerve. 

Branches  of  the  Pneumogastkic  Nerve. — These  may  be  clas.silicd  as 
commimicating  branches  and  branches  of  distribution.  The  communicating  branches 
connect  it  with  the  facial,  glosso-pharyngeal,  spinal  accessory,  hypo-glossal, 
sympathetic,  and  first  two  eervical  nerves.  The  branches  of  distribulion  ■aw  :  in 
the  jugular  foramen,  the  meningeal  and  the  auricular  nerve ;  in  the  neck,  the 
pharyngeal,  superior  laryngeal,  recurrent  laryngeal,  and  cervical  cardiac  nerves ; 
in  the  chest,  the  thoracic  cardiac,  anterior  and  posterior  pulmonary,  and  esopha- 
geal nerves  ;   in  the  abdomen,  gastric  branches. 

The  meningeal  or  recurrent  branch  is  a  small  twig  which  runs  upward  from 
the  ganglion  of  the  root,  through  the  jugular  foramen,  to  the  dura  mater  near  the 
lateral  sinus. 

The  auricular  (Arnold's)  nerve  has  its  origin  from  the  ganglion  of  the  root  of 
the  vagus,  receives  a  branch  from  the  petrous  ganglion  of  the  glosso-pharyngeal 
nerve,  and  passes  over  the  bulb  of  the  internal  jugular  vein  to  reach  an  ajxiture 
in  the  outer  wall  of  the  jugular  fossa.  It  next  passes  through  the  temporal  bone 
near  the  facial  canal,  conmumicating  with  the  facial  nei-ve,  and  emerging  from 
the  bone  between  the  mastoid  process  and  the  external  auditory  meatus.  Turning 
outward,  it  supplies  the  back  of  the  pinna  and  part  of  the  external  auditory  canal, 
one  of  its  branches  communicating  with  the  posterior  auricular  branch  of  the 
facial  ner\'e.  Irritation  of  this  nerve  by  a  foreign  body  in  the  external  auditory 
meatus  may  induce  cough,  which  is  not  relieved  until  the  foreign  body  is  removed. 
This  ear  cough  is  explained  by  reference  of  the  irritation  to  the  mucous  membrane 
of  the  larynx  through  the  auricular  and  superior  larj'ngeal  branches  of  the  pncu- 
mogastric  nerve. 

The  pharyngeal  branch,  the  chief  motor  nerve  of  the  pharynx,  arises  from 
the  ganglion  of  the  trunk  and  receives  part  of  the  accessory  portion  of  the  spinal 
accessory  nerve.  It  runs  behind  or  in  iront  of  the  internal  carotid  artery  to  the 
back  of  the  pharynx,  to  the  upper  border  of  the  middle  constrictor  muscle,  where 
it  assists  in  forming  the  pharyngeal  plexus.  This  plexus  is  formed  by  branches 
of  the  glosso-pharyngeal  nerve,  pneumogastric  nerve,  and  superior  cervical  sympa- 
thetic ganglion.  The  pharyngeal  muscles  and  mucous  membrane  and  the  azygos 
uvulffi  and  levator  palati  muscles  are  supplied  by  filaments  from  this  plexus. 

Tlic  superior  laryngeal  nerve  is  the  sensory  nerve  of  the  larynx.  It  arises 
from  the  ganglion  of  the  trunk  of  the  pneumogastric  ner\'e,  curving  down- 
ward and  forward  behind  the  internal  and  external  carotid  arteries,  and  dividing 


82  SURGICAL  ANATOMY. 

into  the  external  and  internal  laryngeal  branches.  The  internal  branch,  together 
with  the  superior  laryngeal  artery,  enters  the  larynx  througli  the  thyro-hyoid 
membrane,  supplying  the  laryngeal  mucous  membrane  and  the  arytenoid  muscle, 
and  communicating  with  the  recurrent  laryngeal  nerve.  Irritation  of  this  branch, 
as  by  a  crumb  of  bread  or  a  drop  of  water  entering  the  larynx,  causes  a 
momentary  cessation  of  respiration,  cough,  and  expulsion  of  the  intruding  sub- 
stance. The  external  branch,  which  is  smaller  than  the  internal,  descends  along 
the  side  of  the  pharjaix  under  the  sterno-thyroid  muscle ;  it  supplies  the  crico- 
thyroid muscle  and  crico-thyroid  membrane,  the  inferior  constrictor  muscle  of 
the  pharynx,  and  the  thyroid  gland ;  it  also  sends  filaments  to  the  pharyngeal 
plexus,  and  gives  oS,  behind  the  common  carotid  artery,  a  branch  to  the  superior 
cardiac  nerve  of  the  sympathetic. 

Paralysis  of  the  superior  laryngeal  nerve  may  be  due  to  pressure  of  an 
aneurysm  of  the  external  or  the  internal  carotid  artery,  or  to  enlarged  lymphatic 
glands  or  tumors.  The  external  laryngeal  division  may  also  be  compressed  by 
aneurysm  of  the  upper  part  of  the  common  carotid  artery.  Anesthesia  of  the 
laryngeal  mucous  membrane  would  permit  foreign  bodies  to  enter  the  larynx, 
and  cause  inflammation  or  obstruction.  The  vocal  cords  can  not  be  stretched, 
owing  to  paralysis  of  the  crico-thyroid  muscle,  ahd  the  voice  is,  in  consequence, 
hoarse  and  of  low  pitch. 

Irritation  of  the  superior  laryngeal  nerve,  as  by  aneurysm  of  the  internal  or 
external  carotid  artery,  or  by  an  enlarged  thyroid  gland  or  lymphatic  glands, 
causes  peculiar,  ringing  cough,  without  expectoration. 

The  recurrent  or  inferior  laryngeal  nerves  are  the  motor  nerves  of  the 
larynx,  supplying  all  of  the  intrinsic  muscles  of  that  organ  except  the  crico-thyroid 
muscles,  these  being  supplied  by  the  external  laryngeal  branches  of  the  superior 
laryngeal  nerves.  The  right  recurrent  laryngeal  nerve  is  shorter  than  the  left, 
arising  from  the  pneumogastric  nerve  as  it  crosses  the  first  portion  of  the  right 
subclavian  artery.  It  then  winds  behind  the  first  portion  of  the  right  subclavian 
artery,  ascending  obliquely  inward  in  front  of  the  apex  of  the  right  pleural  sac, 
and  l)ehind  the  root  of  the  right  common  carotid  artery  and  the  terminal  portion 
of  the  inferior  thyroid  artery  to  reach  the  groove  between  the  trachea  and 
esophagus.  While  in  this  groove  it  jjasses  behind  and  internal  to  the  right  lateral 
lobe  of  the  thyroid  body,  and  leaves  the  groove  to  reach  the  intrinsic  muscles  of 
the  larynx  by  passing  behind  the  inferior  cornu  of  the  thyroid  cartilage. 

Pressure  upon  this  nerve  may  be  caused  by  aneurysm  of  the  first  portion  of 
the  riglit  .suliclavi;iii  ai'tcry  or  lowcniiost  portion  of  tlie  right  common  carotid 
artery,  by  enhu'gement  of  the  thyroid  body,  cicatrices  of  the  apex  of  the  right 
pleura,  as  in  phthisis,  or  by  malignant  disease  of  the  esophagus. 


DISSECTION  OF  THE  NECK.  83 

The  left  recurrent  laryngeal  nerve  arises  from  the  pneumogastric  nerve  in 
front  of  the  transverse  portimi  nf  the  arch  of  the  aorta,  ami  winds  behind  that 
portion  of  the  arch  helow  and  to  the  left  side  of  the  obliterated  ductus  arteriosus. 
It  next  ascends  behind  the  root  of  the  left  common  carotid  artery  to  the  groove 
between  the  trachea  and  esophagus,  continuing  upward  to  the  larynx,  and  passing 
behind  and  internal  to  the  left  lateral  lobe  of  the  thyroid  body,  in  a  course 
similar  to  that  of  the  right  recurrent  laryngeal  nerve.  Both  nerves  communicate 
with  the  superior  laryngeal  nerve  of  the  same  side,  and  with  the  sympathetic 
nerve. 

Pressure  upon  the  left  recurrent  laryngeal  nerve  may  be  produced  by 
aneurysm  of  the  arch  of  the  aorta  or  of  the  lowermost  portion  of  the  left  common 
carotid  artery,  by  tumors  of  the  posterior  mediastinum,  by  enlargement  of  the 
thyroid  body,  or  ]>y  malignant  disease  of  the  esophagus.  Moderate  pressure  causes 
spasm  of  the  muscles  of  the  same  side  of  the  larynx,  dyspnea,  and  change  of  voice. 
Greater  pressure  causes  paralysis  and  alteration  of  the  voice.  Both  nerves  may 
be  involved  in  labio-glosso-pharyngeal  paralysis  or  disseminated  sclerosis  of  the 
pons,  medulla  oblongata,  and  spinal  cord,  or  by  pressure  from  an  enlarged  thyroid 
body,  or  carcinoma  of  the  esophagus.  When  both  nerves  are  paralyzed  the  vocal 
cords  are  immovable,  phonation  is  imperfect,  and  the  rima  glottidis  is  in  the 
relaxed  attitude  assumed  in  quiet  breathing. 

The  cervical  cardiac  branches  of  the  pneumogastric  nerve  are  given  off  in 
the  upper  and  lower  part  of  the  neck.  The  superior  cervical  cardiac  branches  join 
the  cardiac  branches  of  the  .sympathetic  and  terminate  in  the  deep  cardiac  plexus. 
The  left  inferior  cervical  cardiac  branch  passes  between  the  pleura  and  the  left  side 
of  the  transverse  portion  of  the  aortic  arch,  entering  the  superficial  cardiac  plexus 
■with  the  left  superior  cervical  cardiac  branch  of  the  sympathetic  nerve.  The 
right  inferior  cervical  cardiac  branch  passes  on  the  trachea  to  the  deep  cardiac 
plexus. 

The  thoracic  and  abdominal  branches  of  the  pneumogastric  nerve  are 
described  with  the  thorax  and  abdomen. 

The  Sympathetic. — The  sympathetic  nervous  system  consists  of  a  series  of 
ganglia,  one  ganglion  being  joined  to  another  by  connecting  nerve  cords  ;  it  is  also 
composed  of  gangliated  plexuses,  visceral  ganglia,  and  many  nerve  fibers.  Some 
of  the  ganglia — as,  for  instance,  the  cardiac  ganglia — possess  automatic  action. 
The  nerve  fibers  of  the  sympathetic  system  are  chiefly  non-medullated. 

The  cervical  portion  of  the  sympathetic  nerve  is  situated  behind  the  carotid 
sheath  or  in  its  posterior  wall,  and  lies  beneath  the  prevertebral  fascia,  where  it 
rests  upon  the  rectus  capitis  anticus  major  and  the  longus  colli  mu.sclc.  Three 
cervical  ganglia — the  superior,  middle,  and  inferior — lie  in  each  side  of  the  neck. 


84  SURGICAL  ANATOMY. 

The  superior  cervical  ganglion,  the  largest  of  the  three,  is  a  long,  fusiform 
body  situated  opposite  the  transverse  processes  of  the  second  and  third  cervical 
vertebrae,  behind  the  sheath  of  the  great  vessels.  It  is  formed  probably  by  the 
fusion  of  four  ganglia,  as  it  communicates  with  four  spinal  nerves.  It  gives  off  an 
ascending  and  a  descending  branch,  branches  to  cranial  and  cervical  nerves, 
branches  which  follow  the  external  carotid  artery  and  its  branches,  pharyngeal 
branches,  laryngeal  branches,  and  the  superior  cardiac  nerve. 

The  ascending  branch  passes  upward  through  the  carotid  canal,  with  the  inter- 
nal carotid  artery.  It  divides  into  an  external  and  an  internal  branch.  Its  exter- 
nal branch  forms  the  carotid  plexus,  while  its  internal  branch  forms  the  cavernous 
plexus. 

The  descending  branch  passes  downward  to  the  middle  cervical  ganglion. 

The  branches  to  the  cranial  nerves  communicate  with  the  ganglia  of  the  root 
and  trunk  of  the  pneumogastric  nerve,  the  petrous  ganglion  of  the  glosso-pharyn- 
geal  nerve,  and  the  hypo-glossal  nerve.  No  branches  pass  to  the  spinal  accessory 
nerve.  The  branches  to  the  spinal  nerves  pass  outward  over  the  rectus  capitis 
anticus  major  muscle  to  join  the  upper  four  cervical  nerves. 

The  branches  which  ramify  upon  the  external  carotid  artery  and  its  branches 
(nervi  mollcs)  proceed  from  the  upper  part  of  the  ganglion.  The  nervi  molles 
upon  the  external  carotid  artery  supply  branches  to  the  intercarotid  body  ;  the 
nervi  molles  of  the  facial  artery,  branches  to  the  submaxillary  ganglion  (the  sym- 
pathetic root) ;  those  upon  the  middle  meningeal  artery,  the  sympathetic  root  to 
the  otic  ganglion,  and  the  external  superficial  petrosal  nerve,  which  is  the  sj'm- 
pathetic  root  of  the  geniculate  ganglion  of  the  facial  nerve. 

The  pharyngeal  branches  pass  inward  behind  the  internal  and  external  carotid 
arteries,  and  assists  in  forming  the  pharyngeal  plexus. 

The  laryngeal  branches  join  the  superior  laryngeal  nerve. 

The  superior  cervical  sympathetic  cardiac  nerve  arises  from  the  lower  part  of  the 
superior  cervical  sympathetic  ganglion,  or  from  the  cord  which  runs  to  the  middle 
cervical  ganglion.  It  runs  downward  behind  the  carotid  sheath,  communicating 
with  the  superior  cardiac  branch  of  the  pneumogastric,  the  external  laryngeal,  and 
the  recurrent  laryngeal  nerve.  In  the  chest  the  two  nerves  take  different  courses. 
The  right  superior  cervical  sympathetic  cardiac  nerve  passes  in  front  of  or  behind 
the  first  portion  of  the  subclavian  artery,  following  the  innominate  artery,  and 
terminating  in  the  deep  cardiac  plexus.  On  the  left  side  the  nerve  passes 
between  the  left  common  carotid  and  the  left  subclavian  artery,  and  over  the  left 
side  of  the  arch  of  the  aorta,  to  the  left  of  the  left  pneumogastric  nerve,  terminat- 
ing in  the  superficial  cardiac  plexus. 

The  middle  cervical  or  thyroid  ganglion,  the  smallest  of  the  three  ganglia. 


DISSECTION  OF  THE  NECK.  85 

appears  as  a  swelling  upon  the  sympathetic  cord.  It  may,  however,  be  absent.  It 
rests  upon  or  beneath  the  inferior  thyroid  artery,  opposite  the  transverse  process  of 
the  sixth  cervical  vertebra,  and  is  formed  probably  by  tlie  fu.sion  of  two  ganglia,  as 
it  couununicates  with  two  spinal  nerves.  It  gives  off  conmiunicating  branches  to 
the  superior  and  inferior  cervical  ganglia,  and  to  the  fifth  and  sixth  cervical 
nerves,  thyroid  branches,  and  tlie  middle  cardiac  nerve. 

The  communicating  branch  to  the  superior  ganglion  is  the  cord  of  the  sympa- 
thetic nerve. 

The  commnnicaiing  branches  to  the  inferior  ganglion  arc  the  main  sympathetic 
cord,  which  passes  behind  the  first  portion  of  the  subclavian  arterj',  and  one  or 
two  nerves  which  form  a  loop  (ansa  Vieussenii)  in  front  of  and  below  the  artery. 

The  thyroid  branches  accompany  the  inferior  thyroid  artery  to  the  thyroid 
body. 

The  middle  cardiac  nerve,  the  largest  of  the  three  cervical  sympathetic  cardiac 
nerves,  arises  from  the  middle  ganglion  or  the  sympathetic  cord  just  below  it. 
It  communicates  with  the  .superior  cardiac  and  the  recurrent  laryngeal  nerve,  and 
passes  in  front  of  or  behind  the  first  portion  of  the  subclavian  artery,  entering 
the 'deep  cardiac  plexus. 

The  inferior  cervical  ganglion  is  intermediate  in  size  between  the  middle  and 
superior  ganglia.  It  is  deeply  situated  between  the  transverse  process  of  the 
seventh  cervical  vertebra  and  the  neck  of  the  first  rib,  and  lies  to  the  inner  side 
of  the  superior  intercostal  artery,  behind  the  vertebral  artery.  It  is  formed  prob- 
ably by  the  fusion  of  two  ganglia,  as  it  communicates  witli  two  spinal  nerves,  the 
seventh  and  eighth  cervical.  It  is  joined  to  the  first  thoracic  ganglion  by  two 
large  nerves,  and  may  be  fused  with  that  ganglion.  The  sympathetic  cord  and 
the  ansa  Vieussenii  connect  it  with  the  middle  cervical  ganglion.  It  gives  off  the 
inferior  cardiac  nerve  and  branches  which  form  a  plexus  on  the  vertebral  artery. 

The  inferior  cervical  sympathetic  cardiac  nerve  arises  from  the  inferior  cervical 
ganglion,  or  occasionally  from  the  first  thoracic  ganglion.  It  passes  behind 
the  .subclavian  arterj-,  communicating  with  tlie  recurrent  laryngeal  and  the 
middle  cardiac  nerve,  and  descending  upon  the  trachea  to  enter  the  deep  cardiac 
plexus. 

The  branches  forming  a  plexus  {vertebral  plexvf:)  upon  the  vertebral  artery 
accompany  that  vessel  into  the  cranial  cavity,  after  which  they  follow  the  basilar 
and  cerebral  arteries.  It  is  through  this  plexus  of  nerves  that  contraction  of  the 
pupil  of  the  same  side  results  after  ligation  of  the  vertebral  artery. 

The  External  Carotid  Artery,  so  called  because  it  sujiplies  the  tissues  on  the 
outside  of  the  cranium,  is  the  smaller  of  the  two  terminal  divisions  of  the  common 
carotid  artery.      It  arises  opposite  the  upper   border  of   the    thyroid    cartilage, 


86  SURGICAL  ANATOMY. 

ascends,  and  enters  the  parotid  gland,  where  it  lies  beneath  the  temporo-maxillary 
vein  and  facial  nerve.  Opposite  the  neck  of  the  lower  jaw  it  divides  into  its  two 
terminal  branches,  the  temporal  and  internal  maxillary  arteries.  At  first  it  lies  to 
the  inner  side  of  the  internal  carotid  artery,  but  later  becomes  superficial  to  that 
vessel. 

Relations. — It  is  covered  by  the  skin,  superficial  fascia,  platysma  myoides 
muscle,  superficial  layer  of  the  deep  cervical  fascia,  anterior  border  of  the  sterno- 
mastoid  muscle,  and  a  portion  of  the  parotid  gland,  the  temporo-maxillary  vein, 
and  the  facial  nerve.  It  is  crossed  by  the  hypo-glossal  nerve,  the  facial  and  lingual 
veins,  the  posterior  belly  of  the  digastric  muscle  and  the  stylo-hyoid  muscle,  and 
enters  the  parotid  gland.  Along  the  inner  side  of  the  vessel,  from  below  upward, 
are  the  wall  of  the  pharynx,  the  hyoid  bone,  the  ramus  of  the  lower  jaw,  and  the 
stylo-maxillary  ligament,  from  which  it  is  separated  by  a  portion  of  the  parotid 
gland.  Beneath  it,  near  its  origin,  is  the  superior  laryngeal  nerve  ;  higher  in  the 
neck  the  stylo-glossus  and  stylo-pharyngeus  muscles,  the  stylo-hyoid  ligament,  the 
glosso-pharyngeal  nerve,  the  pharyngeal  branch  of  the  pneumogastric  nerve,  and 
part  of  the  parotid  gland  separate  it  from  the  internal  carotid  artery.  On  its  outer 
side,  at  its  origin,  is  the  internal  carotid  artery.  The  external  carotid  artery  differs 
from  most  of  the  arteries  in  not  having  a  companion  vein,  but  a  vein  formed  by 
the  union  of  the  temporal  and  internal  maxillary  veins  does  occasionally  accom- 
pany it. 

A  line  line  drawn  from  the  junction  of  the  sternum  with  the  clavicle,  to  a 
point  midway  between  the  angle  of  the  lower  jaw  and  the  mastoid  process  repre- 
sents the  course  of  the  common  and  external  carotid  arteries. 

Branches  of  the  External  Carotid  Artery. — These  are  the  superior 
thyroid,  lingual,  facial,  occipital,  posterior  auricular,  ascending  pharjmgeal, 
superficial  temporal,  and  internal  maxillary  arteries.  They  may  be  divided  into 
four  sets  :  an  anterior,  a  posterior,  an  ascending,  and  a  terminal.  The  anterior 
set  comprises  the  superior  thyroid,  lingual,  and  facial ;  the  posterior,  the  occipital, 
and  posterior  auricular ;  the  ascending,  the  ascending  pharyngeal ;  and  the 
terminal,  the  superficial  temporal,  and  internal  maxillary. 

The  superior  thyroid  artery,  the  first  branch  given  off"  from  the  external 
carotid,  arises  just  below  the  greater  cornu  of  the  hyoid  bone.  Throughout  the 
greater  part  of  its  course  it  occupies  the  superior  carotid  triangle.  It  passes 
forward  and  then  downward  and  inward  behind  the  omo-hyoid,  stern o-thyroid,  and 
sterno-hyoid  muscles  to  the  upper  and  front  part  of  the  thyroid  body,  in  which  it 
terminates.  Its  branches  are  the  hyoid,  middle  sterno-mastoid,  superior  laryngeal, 
and  crico-thyroid  arteries. 

The  hyoid  (infra-hyoid)  artery  is  very  small.     It  runs  inward  along  the  lower 


PLATE 


Anterior  Cerebral 

Middle  Cerebra  L , 

Posterior  Cerebral — ., 

Anterior  Cerebellar  -  - 
Internal  Carotid  ■ 


Anterior  communicating 

J\)slCommimicallmf'-  ^^ 
Sup  Cerebellar 


Occipital-  - 
Prin.Cervicis 


Tliyroidea  ima 

Left  Common  Carotid 


-Left  Subclavian 


Transversa  I  IS  colli 
'Suprascapular 

'Aorlu^ 

DIAGRAM    OF    SUBCLAVIAN    AND    CAROTID   ARTERIES 
AND    THEIR  BRANCHES 


87 


PLATE  XIX, 


Supraorbital 
Frontal  veins 


Transverse  facial  v 
Orbitnl  V 


Middle  temporal  v, 
/         Superficial  temporal  v. 


^Communication  v/ith  mastoid  \ 
Occipital  V. 


Angular  v 


VEINS  OF  SCALP,  FACE,  AND  NECK. 
89 


DISSECTION  OF  THE  KECK.  !)1 

border  of  the  hyoid  bone,  beneath  tlie  tliyro-hyoid  muscle,  supplyinj^  tlic  infni- 
liYoid  bursa  and  the  thyro-hyoid  muscle,  and  communicates  witli  tlir  iulVa-liyoHl 
artery  of  the  opposite  side  and  with  the  supra-hyoid  branch  of  the  lingual  artery. 

The  middle  stcrno-madnid  artery  j)asses  downward  and  outward  over  the  sheath 
of  the  common  carotid  artery  in  the  superior  carotid  triangle,  the  triangle  of 
election ;  it  is  chiefly  distributed  to  the  middle  itortion  of  the  sterno-mastoid 
muscle,  supplying  also  tlie  thyro-hyoid,  Kterno-thyroid,  stcrno-hyoid,  cuiin-liydid, 
and  platysma  myoides  muscles,  and  tlie  overlying  skin.  The  autlior  has 
observed  cases  in  which  this  vessel  was  unusually  large,  running  into  the  occipital 
triangle,  and  giving  rise  to  fatal  hemorrhage  following  the  opening  of  an  abscess. 

The  superior  laryngeal  arterij,  larger  than  either  of  the  two  preceding  branches, 
is  accompanied  by  the  internal  branch  of  the  superior  laryngeal  nerve ;  it  passes 
beneath  the  thyro-hyoid  muscle  and  pierces  the  thyro-hyoid  meml)rane,  supj)lying 
the  muscles  and  mucous  membrane  of  the  larynx,  and  anastomosing  with  tiie 
superior  laryngeal  artery  of  the  opposite  side  and  the  inferior  laryngeal  branch  of 
the  inferior  thyroid  artery.  At  times  it  enters  the  larynx  through  a  foramen  in 
the  thyroid  cartilage. 

The  crico-thyroid  artery  runs  across  the  crico-thyroid  membrane,  just  below 
the  lower  border  of  the  tiiyroid  cartilage,  and  is  continuous  with  the  crico-thyi'oid 
artery  of  the  opposite  side.  A  small  branch  usually  passes  through  the  crico- 
thyroid membrane  to  the  interior  of  the  larynx.  The  operation  of  laryngotomy 
is  performed  by  carrying  a  transverse  incision  through  the  crico-thyroid  mcnd)ranc, 
close  to  the  cricoid  cartilage,  and  it  is  therefore  important  to  keep  in  miml  the 
relation  which  the  crico-thyroid  artery  bears  to  the  membrane,  and  the  necessity, 
when  time  is  at  command,  for  exposing  the  membrane  by  careful  dissection. 

The  superior  thyroid  vein,  the  accompanying  vessel  of  the  superior  thyroid 
artery,  crosses  the  terminal  part  of  the  common  carotid  artery,  and  empties  into 
the  internal  jugular  vein  ;  it  may,  at  times,  enter  the  facial  or  lingual  vein.  It 
emerges  from  the  upper  part  of  the  lateral  lobe  of  the  thyroid  Itody,  accompany- 
ing the  superior  thyroid  artery  for  a  .short  distance,  and  then  crossing  the  coinnioii 
carotid  artery  to  empty  into  the  internal  jugular  vein.  A  branch  of  the  vein,  or 
one  which  arises  separately  in  the  thyroid  body,  usually  passes  upward  and  anterior 
to  the  common  carotid  and  the  external  carotid  artery,  and  empties  into  the  lin- 
gual vein. 

The  lingual  artery,  the  second  branch  of  the  external  carotid,  arises  opposite 
the  greater  cornu  of  the  hyoid  bone  between  the  superior  thyroid  and  facial  arte- 
ries, occasionally  arising  as  a  common  trunk  with  the  latter.  It  consists  of  three 
portions :  the  first  or  oblique,  which  lies  between  its  origin  and  the  outer  border 
of  the  hyo-glossus  muscle  ;  the  second  or  horizontal  jiortion,  beneath  the  hyo-glossus 


92  SURGICAL  ANATOMY. 

muscle  and  parallel  with  the  greater  cornu  of  the  hyoid  bone;  and  the  tJiird  or 
ascending  portion,  between  the  hyo-glossus  and  the  genio-hyo-glossus  muscle.  The 
first  or  oblique  portion  lies  in  the  superior  carotid  triangle,  and  runs  upward  and 
inward  to  the  upper  border  of  the  greater  cornu  of  the  hyoid  bone,  resting  upon 
the  middle  constrictor  muscle  of  the  pharynx  and  the  internal  laryngeal  branch  of 
the  superior  laryngeal  nerve.  Thence  it  passes  beneath  the  hj'o-glossus,  the  pos- 
terior belly  of  the  digastric,  and  the  stylo-hyoid  muscle,  emerging  from  the 
superior  carotid  triangle  and  entering  the  submaxillary  triangle.  This  portion  of 
the  vessel  is  crossed  by  the  hypo-glossal  nerve  and  lingual  vein,  and  gives  off 
the  supra-hyoid  branch.  The  second  or  horizontal  portion  runs  beneath  the  hyo- 
glossus  muscle.  (See  description  of  submaxillary  triangle.)  The  third  or  ascend- 
ing portion  runs  beneath  the  anterior  border  of  the  hyo-glossus  on  the  outer  aspect 
of  the  genio-hyo-glossus  muscle,  and  runs  forward  to  the  tip  of  the  tongue, 
terminating  as  the  ranine  artery;  the  terminal  portion  of  the  lingual  artery  is 
separated  from  the  cavity  of  the  mouth  by  the  mucous  membrane  which  lines  it. 
(See  description  of 'submaxillary  triangle.) 

The  lingual  vein  is  seen  crossing  the  first  portion  of  the  lingual  artery  with  the 
hypo-glossal  nerve.  It  runs  over  the  external  carotid  arterj^  and  opposite  the 
greater  cornu  of  the  hyoid  bone  empties  into  the  internal  jugular  vein  sejmrately, 
or  by  a  common  trunk  with  the  facial  vein  and  a  brancli  of  the  siiperior  thyroid 
vein.  These  veins  and  their  common  trunk  may  cau.se  some  difficulty  in  ligation 
of  the  common  carotid  or  first  portion  of  the  lingual  artery. 

The  facial  artery  (external  maxillarj')  arises  from  the  external  carotid  above 
the  lingual  artery,  passes  upward  beneath  the  posterior  belly  of  the  digastric  and 
the  stylo-hyoid  muscle  and  the  submaxillary  gland,  being  embedded  in  a  groove 
on  the  under  surface  of  the  latter ;  it  then  cur\'es  upward  over  the  body  of  the 
lower  jaw,  reaching  the  face  at  the  anterior  inferior  angle  of  the  masseter  muscle, 
where  the  artery  can  be  compressed  and  its  pulsations  readily  felt.  It  consists  of 
two  portions,  a  cervical  and  a  facial. 

Tlie  Branches  given  off  from  the  ceiTical  portion  of  the  facial  artery  are 
the  ascending  or  inferior  palatine,  the  tonsillar,  the  submaxillary,  the  submental, 
and  the  muscular. 

The  ascending  or  inferior  palatine  artery  occasionally  arises  separatel}^  from 
the  external  carotid  artery.  It  ascends  between  the  internal  and  external  carotid 
arteries,  then  runs  between  the  stylo-glossus  and  stylo-pharyngeus  muscles,  and 
finally  between  the  internal  pterygoid  muscle  and  the  superior  constrictor  muscle  of 
the  pharynx.  Reaching  the  levator  palati  muscle,  it  divides  into  two  branches : 
one,  the  palatine,  follows  the  course  of  the  levator  palati  mu.scle  to  supply  the  soft 
palate,  and  anastomoses  with  the  ascending  palatine  artery  of  the  opposite  side,  the 


! 


DISSECTION  OF  THE  NECK.  93 

descending  palatine  brancli  of  Uie  internal  niaxiilaiy  artery,  and  the  aseendiug 
pharvn^val  artery;  the  dther  hranch,  the  tonsillar,  perforates  the  supfrior  eon- 
strietormuscle  of  the  pharynx,  and  snpplies  the  tonsil  and  the  Eustaehiaii  tube, 
anastomoses  with  the  tonsillar  branehes  of  the  ascending  pharyngeal  and  facial 
arteries,  and  with  the  descending  or  posterior  palatine  branch  of  the  internal  max- 
illary artery. 

The  (oiisilliir  artcrii,  smaller  than  the  ascending  palatine  artery,  passes  up- 
ward between  the  internal  pterygoid  and  the  stylo-glossus  muscle.  It  perforates 
the  superior  constrictor  muscle  of  the  ])harynx  ojiposite  thr  tonsil,  ami  supplies 
branches  to  the  tonsil  and  root  of  the  tongue.  It  anastomo.scs  with  the  tonsillar 
branch  of  the  ascending  palatine  and  the  other  tonsillar  arteries. 

The  glandular  (submaxillary)  branches,  three  or  four  in  number,  supjtly  the 
submaxillary  gland,  and  are  derived  from  the  portion  of  the  artery  in  contact 
with  the  gland  ;  some  twigs  usually  run  to  Whai'ton's  duct. 

The  submental  artery  is  the  largest  of  the  branches  given  off  from  the 
cervical  portion  of  the  facial  artery.  It  arises  from  this  vessel,  beneath  the  sub- 
maxillary gland.  It  next  runs  forward  upon  the  mylo-hyoid  muscle,  under  the 
lower  border  of  the  lower  jaw,  and  beneath  the  anterior  belly  of  the  digastric 
muscle,  to  the  symphysis  of  the  lower  jaw,  where  it  ilivides  into  a  superficial  and 
a  deep  branch.  The  superficial  branch  winds  over  the  lower  jaw  and  runs  in 
the  superficial  fascia  of  the  chin,  anastomosing  with  the  inferior  labial  artery. 
The  deep  branch  runs  beneath  the  depres.sor  labii  inferioris  muscle,  and  anasto- 
moses with  the  inferior  labial  and  mental  arteries.  Its  branches. are  muscular, 
which  supply  the  adjacent  muscles ;  perforating,  which  pierce  the  mylo-hj'oid 
muscle  to  anastomose  with  the  sublingual  artery ;  and  cutaneous,  to  the  overlying 
skin. 

The  muscular  branches  supply  the  posterior  belly  of  the  digastric,  the  stylo- 
hyoid, the  stylo-glossus,  the  mylo-hyoid,  and  the  internal  pterygoid  muscle. 

The  facial  vein  leaves  the  face  at  the  anterior  inferior  angle  of  the  masseter 
muscle.  It  passes  over  the  submaxillary  gland,  the  stylo-hyoid  and  posterior  belly 
of  the  digastric  muscle,  which  separate  it  from  the  Axcial  artery.  It  receives  the 
anterior  division  of  the  temporo-maxillary  vein,  crosses  the  external  carotid  artery, 
and  empties  into  the  internal  jugular  vein  opposite  the  greater  cornu  of  the  hyoid 
bone.  It  may  be  injured  in  opening  abscesses  situated  where  it  passes  over  the 
svibmaxillary  gland. 

The  occipital  artery,  quite  a  large  vessel,  is  one  of  the  posterior  branches  of 
the  external  carotid  artery.  It  arises  opposite  the  facial  artery,  near  the  lower 
border  of  the  posterior  belly  of  the  digastric  muscle,  along  which  it  runs  to  the 
interval   between  the  mastoid  process  of  the  temporal  bono  and    the    transverse 


94  SURGICAL  ANATOMY. 

process  of  the  atlas,  to  reach  the  groove  on  the  under  surface  of  the  mastoid  portion 
of  the  temporal  bone.  At  its  origin  it  is  crossed  by  the  hypo-glossal  nerve.  On  its 
way  to  the  mastoid  process  it  crosses  the  internal  carotid  artery,  the  internal  jugu- 
lar vein,  the  i^neumogastric,  hypo-glossal,  and  spinal  accessory  nerves,  and  passes 
beneath  the  lower  portion  of  the  parotid  gland.  It  runs  horizontally  backward 
through  the  occipital  groove  of  the  temporal  bone,  covered  by  all  the  muscles 
attached  to  the  mastoid  process, — the  sterno-mastoid,  splenius  capitis,  trachelo- 
mastoid,  and  posterior  belly  of  the  digastric  muscle, — and  lies  upon  the  superior 
oblique  and  complexus  muscles.  Reaching  the  back  of  the  head,  the  artery 
pierces  the  trapezius  muscle  close  to  the  superior  curved  line  of  the  occipital  bone, 
ascends,  and  divides  into  branches,  as  described  under  the  Dissection  of  the  Scalp. 
As  it  pierces  the  trapezius  muscle  and  ramifies  in  the  superficial  fascia  of  the 
scalp,  it  is  accompanied  by  the  great  occipital  nerve.  This  vessel  is  conveniently 
divided  by  the  sterno-mastoid  muscle  into  three  parts, — a  first,  a  second,  and  a 
third  portion, — situated  respectively  internal  to,  beneath,  and  external  to  that 
muscle.  The  first  portion  is  covered  only  by  skin  and  fasciae,  except  where  it 
is  overlapi^ed  by  the  posterior  belly  of  the  digastric  muscle,  the  parotid  gland, 
and  the  temporo-maxillary  vein.  It  is  crossed  by  the  hypo-glossal  nerve.  Behind 
it  successively  lie  the  internal  carotid  artery,  the  hypo-glossal  and  the  pneumo- 
gastric  nerve,  the  internal  jugular  vein,  and  the  spinal  accessory  nerve.  The 
first  portion  of  the  artery  is  the  2}t(t<^c  of  election  for  ligation.  An  incision  is  car- 
ried along  the  anterior  border  of  the  upper  part  of  the  sterno-mastoid  muscle  while 
the  neck  is  well  extended.  The  skin,  superficial  fascia,  platysma  mj'oides  muscle, 
and  the  superficial  layer  of  the  deep  fascia  are  divided,  and  the  artery  is  seen  run- 
ning parallel  with  or  beneath  the  lower  border  of  the  digastric  muscle.  The  hypo- 
glossal nerve  will  be  seen  curving  around  the  artery  at  its  origin.  The  second  por- 
tion dips  deeply  under  the  digastric  muscle  between  the  mastoid  process  of  the 
temporal  bone  and  the  transverse  process  of  the  atlas,  being  covered,  as  previously 
stated,  by  the  muscles  attached  to  the  mastoid  process,  and  Ijang  successively  against 
the  rectus  capitis  lateralis,  which  separates  it  from  the  vertebral  artery,  the  mastoid 
portion  of  the  temporal  bone  while  piassing  through  the  occipital  groove,  and  finally 
against  the  insertion  of  the  superior  oblique  muscle.  The  third  portion  emerges 
from  beneath  the  posterior  border  of  the  sterno-mastoid  and  splenius  muscles,  lying 
upon  the  complexus  in  the  triangular  interval  between  the  sterno-mastoid  and 
the  trapezius,  and  piercing  the  trapezius  muscle  about  midway  between  the 
mastoid  process  and  the  external  occipital  protulierancc,  to  become  subcutaneous 
and  pass  ujiwnrd  in  the  superficial  fascia  of  the  scalp.  It  is  accompanied  by  the 
great  occipital  nerve. 

The  Branchks  given  off  from  the  occipital  artery  are  flic  nniscular,  superior 


DISSECTION  OF  THE  NECK.  95 

sterno-mastoid,  auricular,  posterior  meningeal,  mastoid,  princeps  cervicis,  coiunumi- 
cating,  and  terminal. 

The  muscular  branches  supply  the  digastric,  stylo-hyoid,  splenius,  trachclo- 
mastoid,  trapezius,  recti,  superior  and  inferior  oblique,  and  the  occipitalis  muscles. 
The  superior  sterno-mastoid  artery  enters  the  sterno-mastoid  muscle  %vith  the 
spinal  accessory  nerve.  It  arises  from  the  first  portion  of  the  occipital  artery,  and 
passes  downward  and  backward  over  the  hypo-glossal  nerve  to  enter  the  sterno- 
mastoid  muscle. 

The  auricular  branch  supplies  the  back  of  the  pinna.  At  times  it  is  large  and 
takes  the  place  of  the  posterior  auricular  arterj'' ;  it  may  send  a  branch  to  the 
dura  mater  through  the  mastoid  foramen. 

The  posterior  meningeal  branches  ascend  along  the  internal  jugular  vein,  and 
enter  the  cranial  cavity  through  the  jugular  foramen  to  supply  the  dura  mater  of 
the  posterior  cranial  fossa. 

The  mastoid  branch  is  a  small  vessel  which  traverses  the  mastoid  foramen  to 
supply  the  diploe,  the  walls  of  the  lateral  sinus,  the  dura  mater,  and  the  mas- 
toid air  cells. 

The  princeps  cervicis  artery  is  the  largest  branch  of  the  occipital  artery.  It 
nnis  down  the  back  of  the  neck  between  the  splenius  and  the  complexus  muscle, 
and  divides  into  a  superficial  and  a  deep  branch.  The  superficial  branch  pierces  the 
splenius  and  runs  between  it  and  the  trapezius,  supplying  these  muscles  and 
anastomosing  with  the  superficial  cer\'ical  artery,  one  of  the  terminal  branches  of 
the  transversalis  colli ;  the  deep  branch  descends  between  the  complexus  and  semi- 
spinalis  colli,  supplies  these  muscles,  and  anastomoses  with  branches  of  the  verte- 
bral and  with  the  deep  cervical  branch  of  the  superior  intercostal  artery.  The 
anastomoses  between  the  occipital,  vertebral,  and  superior  intercostal  arteries  play 
an  important  part  in  the  formation  of  the  collateral  circulation  after  ligation  of  the 
common  carotid  or  the  subclavian  artery. 

Communicating  branches  ran  between  the  recti  and  the  superior  and  inferior 
oblique  muscles  to  anastomose  with  branches  of  the  vertebral  artery. 

The  terminal  branches  pass  laterally  and  mesially  upward  in  the  superficial 
fascia  of  the  occipital  region  of  the  scalp  to  supply  the  scalp  and  pericranium,  and 
are  known  as  external  and  internal.  They  anastomose  M-ith  the  occipital  artery  of 
the  opposite  side,  the  posterior  auricular  and  the  superficial  temporal  artery. 

The  occipital  vein  accompanies  the  third  portion  of  the  occipital  artery ;  it 
communicates  with  the  lateral  sinus  tln-ough  the  mastoid  foramen,  and  with 
the  diploic  veins,  piercing  the  trapezius  muscle  with  the  occipital  arterj'.  It 
enters  the  occipital  triangle  and  terminates  in  the  deep  cervical  vein,  or  it  may 
bifiircate,  one  subdivision  emptying  into  the  posterior  jugular  vein,  and  the  other 


96  SURGICAL   ANATOMY. 

into  the  deep  cervical  vein.  The  deep  cervical  vein  accompanies  the  deep  branch  of 
the  princeps  cervicis  artery,  then  the  profunda  cervicis,  passes  between  the  trans- 
verse process  of  the  seventh  cervical  vertebra  and  the  neck  of  the  first  rib,  and 
empties  into  the  innominate  or  vertebral  vein. 

The  posterior  auricular  artery,  the  remaining  posterior  branch  of  the 
external  carotid,  is  smaller  than  the  occipital  artery,  and  arises  just  above  the  pos- 
terior belly  of  the  digastric  muscle.  It  ascends  obliquely  upward  and  backward  in 
the  parotid  gland,  to  the  furrow  between  the  pinna  of  the  ear  and  the  mastoid 
process  of  the  temporal  bone,  passing  below  the  facial  nerve  and  over  the  spinal 
accessory  nerve.  Immediately  above  the  mastoid  process  it  divides  into  two 
branches — an  anterior,  which  passes  forward  and  anastomoses  with  the  posterior 
division  of  the  temporal  arterj^  and  a  posterior,  which  anastomoses  with  the  occi- 
pital artery. 

The  Branches  of  the  posterior  auricular  artery  are  the  parotid,  muscular, 
stylo-mastoid,  auricular,  and  mastoid. 

The  parotid  branches  supply  the  lower  end  of  the  parotid  gland,  anastomos- 
ing with  other  arteries  distributed  to  the  gland.  ' 

The  muscular  branches  supply  the  digastric,  stylo-hyoid,  sterno-mastoid,  and 
retrahens  aurem  muscles. 

The  stijlo-rnastoid  branch  enters  the  stylo-mastoid  foramen  of  the  temporal 
bone,  and  supplies  the  tympanum,  the  mastoid  cells,  and  the  semicircular  canals. 
In  the  fetus  a  branch  of  the  stylo-mastoid  artery  forms,  with  the  tympanic  branch 
from  the  internal  maxillary  artery,  a  vascular  circle  around  the  circumference  of 
the  tympanic  membrane ;  from  this  circle  smaller  vessels  are  given  off,  which 
ramify  upon  the  membrane.  From  the  acjueduct  of  Fallopius  it  sends  branches 
to  the  external  auditory  meatus  {meatal) ;  to  the  mastoid  cells  and  mastoid  antrum 
(mastoid) ;  to  the  staj^edius  muscle  (stapedic) ;  to  the  tympanum,  forming  the  anas- 
tomotic circle  in  the  fetus  {tympanic) ;  to  the  vestibule  and  semicircular  canals 
(vestibular);  and  a  final  twig  (fermiTirr/),  which  accompanies  the  great  superficial 
petrosal  nerve  through  the  hiatus  Fallopii  and  anastomoses  with  the  petrosal 
branch  of  the  middle  meningeal  arteiy. 

The  auricular  branch  (anterior  terminal)  supplies  the  back  part  of  the  auricle, 
and  anastomoses  with  the  posterior  temporal  and  auricular  branch  of  the  superficial 
temporal  artery  ;  some  of  its  branches  perforate  the  cartilage  of  the  pinna  to  supply 
its  anterior  surface. 

Tlie  mastoid  branch,  (occipital  branch)  crosses  the  insertion  of  the  sterno- 
mastoid  muscle,  supplies  the  structures  over  the  mastoid  process,  and  anastomoses 
with  the  occipital  artery. 

The  posterior  auricular  vein,  wliich  is  of  considerable  size,  accompanies  the 


DISSECTIOX  OF  Till':  .\KVk'.  97 

terminal  pDrtioii  of  tlic  posteiior  auricular  artery  and  juius  the  posterior  liivisinn  oi" 
the  temporo-niaxillaiy  vein  to  form  the  external  jugular  vein. 

The  posterior  auricular  nerve. — liunniiii;-  close  to  the  posterior  aurieular 
artery  is  tiie  posterior  aurieular  nervi',  the  first  branch  given  off  from  the  facial 
after  its  exit  from  the  stylo-mastoid  foramen.  It  ascends  in  front  of  the  mastoid 
process,  where  it  communicates  with  the  great  auricular  nerve  and  the  aurieular 
branch  of  the  pneumogastric  nerve.  Between  tlie  mastoid  process  and  tlic  external 
auditory  meatus  it  divides  into  two  branches  :  an  anterior,  which  supplit's  tlie 
retrahens  aurena  and  the  small  muscles  on  the  back  of  the  pinna,,  and  a.  posterior 
occipital,  the  larger,  which  passes  along  the  superior  curvdl  line  of  the  occijutal 
bone,  supplying  the  occipitalis  muscle  and  communicating  with  the  small  oceijiital 
nerve. 

The  ascending  pharyngeal  artery,  a  long,  slender  brandi,  the  smallest 
given  otf  from  the  external  carotid  arterj',  arises  from  the  back  part  of  tliat  artery, 
about  one-half  of  an  inch  above  the  bifurcation  of  the  common  carotid  artery. 
At  times,  liowever,  it  arises  from  the  common  carotid  artery.  It  is  situated  deep 
in  the  neck,  in  relation  with  tlie  internal  carotid  artery,  and  lies  upon  the  rectus 
capitis  anticus  major  muscle.  It  ascends  between  the  internal  carotid  artery 
and  the  side  of  the  pharynx,  and  beneath  the  stylo-pharyngeus  muscle  and  the 
glosso-pharyngeal  nerve,  to  the  base  of  the  skull  :  here  it  enters  the  pharynx 
al)ove  the  superior  constrictor  muscle,  to  end  in  the  soft  palate.  It  gives  off 
prevertebral,  pharyngeal,  meningeal,  palatine,  and  tympanic  branches. 

The  prevertebral  branches  are  small  vessels  which  pass  outward  to  supply  the 
rectus  capitis  anticus  major  and  minor  muscles,  the  sympathetic,  pneumogastric, 
and  hypo-glossal  nerves,  and  the  deep  cervical  chain  of  lymphatic  glands.  They 
anastomose  with  the  ascending  cervical  artery. 

The  pharyngeal  branches,  three  or  four  in  number,  supply  the  upper  and 
middle  constrictor  muscles,  the  mucous  membrane  of  the  pharynx,  and  the  stylo- 
pharyngeus  muscle.  The  largest  of  these  branches,  the  palatine,  enters  the 
pharynx  above  the  superior  constrictor  muscle,  and  terminates  in  the  soft  palate, 
the  Eustachian  tube,  and  the  ton.sil ;  it  takes  the  place  of  the  ascendijig  palatine 
branch  of  the  facial  artery  when  this  vessel  is  small. 

The  meningeal  branches,  three  in  immber,  enter  the  cranial  cavity  through 
the  jugular  foramen,  in  company  with  the  internal  jugular  vein,  through  tiie 
anterior  condyloid  and  middle  lacerated  foramina,  to  supply  the  dura  mater. 

The  tympanic  branch  traverses  the  tympanic  canaliculus,  together  with  the 
tympanic  branch  of  the  glosso-pharyngeal  nerve,  enters  the  tympanum,  anasto- 
moses with  the  other  tympanic  arteries,  and  supplies  the  adjacent  structures. 

The  descending  pharyngeal  vein  arises  in  a  minute  plexus  at  the  back  part 

S—      II-7 


98  SURGICAL  ANATOMY. 

and  side  of  the  pharynx.  After  receiving  meningeal  l>ranches,  the  veins  from  the 
soft  palate  and  Eustachian  tube,  and  the  Vidian  vein,  it  terminates  in  the  in- 
ternal jugular  vein.     It  occasionally  em[)ties  into  the  facial  vein. 

Internal  maxillary  and  temporal  arteries. — The  description  of  the  internal 
maxillary  arter}-  is  given  under  the  Dissection  of  the  Pterygo-maxillary  Region. 
The  temporal  artery  is  described  under  the  Dissection  of  the  Face. 


The  Submaxillary  Triangle  (continued). — 

The  digastric  muscle  consists  of  two  muscular  bellies,  an  anterior  and  a 
posterior,  united  by  an  intervening  tendon.  The  posterior  belly,  the  larger  of  the 
two,  arises  from  the  digastric  groove,  which  lies  to  the  inner  side  of  the  base  of  the 
mastoid  process  of  the  temporal  bone ;  the  anterior  belly,  the  shorter  of  the  two, 
arises  from  the  depression  on  the  deep  surface  of  the  lower  jaw  at  the  side  of  the 
symphysis.  The  fibers  of  the  posterior  belly  are  directed  downward,  forward,  and 
inward  ;  those  of  the  anterior,  downward  and  backward  to  the  intervening  tendon, 
which  pierces  the  stylo-hyoid  muscle,  and  is  connected  to  the  side  of  the  bodj^  of 
the  hyoid  bone  by  a  jirocess  of  the  deep  cervical  fascia  lined  with  a  synovial  mem- 
brane. A  broad  aponeurotic  expansion — the  supra-hyoid  aponeurosis — is  given  off 
on  each  side  from  the  tendon  of  the  digastric  muscle,  and  is  attached  to  the  body 
and  greater  cornu  of  the  hj'oid  bone  and  to  aponeurotic  expansion  of  the  opposite 
side,  so  that  the  interval  between  the  anterior  bellies  of  the  digastric  muscles  is 
occupied  by  this  expansion.  The  posterior  belly  passes  over  the  sheath  of  the 
carotid  vessels,  the  hypo-glossal  and  spinal  accessory  nerves,  and  beneath  the 
sterno-mastoid  and  trachelo-mastoid  muscles.  The  occipital  artery  passes  upward 
and  backward  along  the  lower  border  of  the  posterior  belly.  The  anterior  belly 
may  be  absent  and  the  posterior  belly  may  be  double.  At  times  accessory  slips 
join  the  posterior  belly  from  the  styloid  pi'ocess  or  pharynx. 

Nerve  Supply. — The  posterior  bell}'  of  the  digastric  muscle  is  supplied  by  a 
branch  from  the  facial  nerve ;  the  anterior  belly,  by  the  mylo-hyoid,  a  branch  of 
the  inferior  dental  nerve. 

Br,ooD  Supi'LY. — From  muscular  branches  of  the  facial,  occipital,  and  poste- 
rior auricular  arteries. 

Action. — It  depresses  the  lower  jaw  and  assists  in  opening  tin-  nmutli.  If 
tlic  ](i\ver  jaw  b(^  fixed,  the  (wo  bellies  acting  together  wnuld  raise  (he  liy<ii<l  bone, 
as  in  degli;tition. 

The  stylo-hyoid  muscle  is  slender,  has  about  the  same  position  as  the  poste- 


PLATE  XX. 


External  carotid  a.      Stylo-hyoid  m 


internal  maxillafy  v 
Temporal 
Posterior  auricular  a 
Posterior  auricular 


Complexus  m 


jPosterror  belly  of  digastric  m. 
Occipital  a. 
Lingual  V. 
Lingual  a. 

Facial  v. 


Anterior  bellies  of 
digastric  muscles 


Levator  anguli  scapulae  m 

Ttansversalls  colli  v 
Serratus  magnus 
Posterior  belly  of  omo-hyoid 

Scalenus  medius  m 


Suprascapular  a. 
Suprascapular  v. 
Subclavian  a. (3d  portion) 
Transversalis  colli  a. 


Sterno-thyroid  m* 


SUPERFICIAL  STRUCTURES  OF  NECK, 
100 


PLATE  XXI. 


Facial 
Posterior  auricular  n.and  v 


Nerve  to  stylo-hyoid  m.and  posterior  belly  of  digastric  m. 
Hypoglossal  n. 

Descendens  hypoglossi  n. 


Superficial  cervical  n 
Posterior  thoracic  n 
Suprascapula 


Brachial  plexus 


SUPERFICIAL  STRUCTURES  OF  NECK. 
101 


DISSECTION  OF  THE  NECK.  103 

rior  belly  of  tlic  digastrio,  ami  lies  in  ciuitact  with  {W  upjaT  iKink'r  ol'  the  iioslcriur 
lii'lly  of  the  digastric  muscle.  It  arises  from  the  iiiiilillc  n^  the  (mtcr  >urfai'c  df  the 
styloid  process  of  the  temporal  bone,  whence  it  passes  downwanl  and  forw^ird  to 
be  inserted  into  the  outer  surface  of  the  hyoid  bone  where  the  greater  eornu 
joins  the  body.  It  lies  above  the  posterior  belly  of  the  digastric  muscle,  and  is 
pierced  near  its  insertion  hy  tlie  tt'udon  of  the  digasti-ic.  In  some  cadavers  the 
stylo-hyoid  muscle  is  absent. 

Nerve  Supply. — From  the  facial  nerve. 

Blood  Supply. — From  the  nuiscular  twigs  of  the  facial,  occipital,  and  ]io.ste- 
rior  auricular  arteries. 

Action. — It  raises  and  draws  tiic  hyoid  bone  backward,  thus  preventing  the 
rrturn  of  ludd  into  the  pliarynx  during  deglutition. 

The  submaxillary  gland,  one  of  the  three  salivary  glands,  is  situated  in  the 
submaxillary  triangle  and  extends  upward  under  the  body  of  the  lower  jaw  as  far 
as  the  attachment  of  the  mylo-hyoid  muscle.  It  weighs  about  two  (h-ams.  It 
consists  of  a  larger  superficial  portion  and  a  smaller  deep  portion.  The  superficial 
portion  of  the  gland  is  covered  by  the  skin,  superficial  fascia,  platysma  myoides 
muscle,  infra-maxillary  branches  of  the  facial  nerve,  superficial  layer  of  the  deep 
fascia,  facial  vein,  some  lymphatic  glands,  and  the  bo<ly  of  the  lower  jaw  ;  it  rests 
upon  the  mylo-hj'oid,  hyo-glossus,  and  stylo-glossus  muscles,  the  facial  artery, 
suljmental  artery,  mylo-hyoid  artery  and  nerve,  and  the  hypo-glossal  nerve  and 
lingual  vein  ;  in  front  of  it  lies  the  anterior  belly  of  the  digastric  muscle  ;  behind 
it  is  the  stylo-maxillary  ligament,  which  sejiarates  it  from  the  parotid  gland. 
Its  deep  .surface  contains  a  groove  for  the  facial  arteiy.  The  deep  portion  ami 
duct  of  the  gland  (Wharton's  duct),  which  dip  under  the  posterior  Ijorder  of  the 
mylo-hj'oid  muscle,  will  be  described. 

Blood  Supply. — From  branches  of  the  facial  and  lingual  arteries. 

Nerve  Supply. — From  branches  of  the  submaxillary  ganglion,  through 
which  it  receives  filaments  from  the  gustatory  and  chorda  tympani  nerves.  It  also 
receives  branches  from  the  mylo-liyoid  nerve  and  from  the  sympathetic  plexus 
around  the  facial  artery. 

Dissection. — Reflect  the  submaxillary  gland  upward  without  dividing  the 
facial  vein,  which  runs  over  the  gland,  or  the  facial  and  submental  arteries,  which 
are  beneath  it.  The  submaxillary  branches  of  the  facial  artery  which  supply  the 
gland  must  be  divided.  This  exposes  a  portion  of  tlie  facial  artery  and  its  infra- 
maxillary  branches,  the  mylo-hyoid  artery  and  nerve,  a  part  of  the  hypo-glossal 
nerve  and  lingual  vein,  the  mylodiyoid,  hyo-glo.ssus,  and  stylo-glossus  muscles. 

The  cervical  portion  of  the  fecial  arter\'  and  its  sul)maxillary,  submental, 
ascending  palatine,  and  tonsillar  braTiches  have  been  described. 


104  SURGICAL   ANATOMY. 

Tlie  mylo-hyoid  nerve,  a  branch  of  the  inferior  dental  nerve,  maj'  be  seen 
emerging  from  between  the  lower  jaw  and  the  internal  pterygoid  muscle.  It  runs 
forward  with  the  submental  artery  upon  tlie  mylo-hyoid  muscle,  to  terminate  in 
the  anterior  belly  of  the  digastric  muscle,  supplying  the  mylo-hyoid  and  the  ante- 
rior belly  of  the  digastric  muscle. 

The  mylo-hyoid  artery  accompanies  the  mylo-liyoid  nerve  between  the 
internal  pterygoid  muscle  and  lower  jaw,  and  anastomoses  with  the  submental  and 
dorsalis  lingute  arteries. 

The  hypo-glossal  nerve,  the  motor  nerve  of  the  tongue,  is  the  twelfth  or  last 
of  the  cranial  nerves.  It  leaves  the  cranial  cavity  at  the  anterior  condyloid  fora- 
men, and  descends  almost  vertically  toward  the  angle  of  the  lower  jaw,  lying  at 
first  deeply  Iseneath  the  internal  jugular  vein  and  internal  carotid  artery,  and  is 
intimately  connected  with  the  lower  ganglion  (ganglion  of  the  trunk)  of  the 
pneumogastric  nerve.  It  then  passes  forward  between  the  internal  jugular  vein 
and  the  internal  carotid  arterj',  and  beneath  the  posterior  belly  of  the  digastric 
muscle,  at  the  lower  border  of  which  it  becomes  more  superficial  and  enters 
the  superior  carotid  triangle.  It  next  passes  over  the  internal  carotid  and 
curves  around  the  occipital  artery,  at  its  origin  from  the  external  carotid 
artery ;  thence  it  continues  forward  over  tlie  external  carotid  and  facial  arteries, 
and  near  the  greater  cornu  of  the  hyoid  bone,  over  the  superior  laryngeal  nerve, 
the  middle  constrictor  muscle  of  the  pharynx,  and  the  hyo-glossus  muscle, 
forming  a  loop  the  convexity  of  which  is  directed  downward  and  outward.  At 
the  anterior  border  of  the  hyo-glossus  muscle  it  communicates  with  the  gustatory 
or  lingual  nerve.  It  pa.sses  beneath  the  tendon  of  the  digastric,  the  stylo- 
hyoid, and  the  mylo-hyoid  muscle.  After  running  beneath  the  stylo-hyoid  and 
the  posterior  part  of  the  tendon  of  the  digastric  muscle,  it  lies  in  the  submaxillary 
triangle  ui>on  the  hyo-glo.s.sus  muscle,  and  beneath  the  submaxillary  gland. 
Here  it  forms  the  base  of  the  lingual  triangle,  and  lies  above  the  lingual  vein. 
It  supplies  all  of  the  extrinsic  muscles  of  the  tongue,  the  thyro-hyoid,  and  through 
the  descendens  hypoglossi  nerve  assists  in  supplying  tlie  onio-hyoid,  sterno-hyoid, 
and  sterno-thyroid  muscles.  The  branch  to  tlie  thyro-hyoid  muscle  is  given  off 
near  the  tip  of  the  greater  cornu  of  the  hyoid  bone,  and  passes  obli(jUcly  down- 
ward and  forward  to  reach  the  superficial  surface  of  that  muscle. 

Paralysis  of  one  Jiypo-fjlossal  nerve  causes  wasting  and  flabbiness  of  the  corre- 
sponding half  of  the  tongue  ;  when  the  tongue  is  protruded,  the  tip  of  the  organ  is 
carried  townnl  the  paralyzed  side. 

Dissection. — In  <'(iin|ili'liiig  llie  ilisscctidu  i)f  llie  submaxillai'v  triangle,  the 
anterior  belly  of  tlie  digastric  uuiscle  slmulil  be  detached  from  llie  knwr  jaw  and 
dis]ilaccd   downward,  wluii   the   inylii-liyoiil,  the  muscle   forming   the  greater  jiart 


PLATE  XXII 


Posterior  hr.  of 
descend incj palatine  A 

Pal  aline  hr.  of 
ascending  pharyngeal  A 

Ascending  pharyngeal  A. 

Ascending  palalinc  hr 
•^  'of facial  A 
Tonsillar    br. — 
of  facial  A. 
Stylo- pharyngeus  M- 

Facial  A. 

Middle  conslriclorM .- 
Dors  alls  linguae  A. 

Lingual  A. 
External  carol  id  A. ^ 


Superior  Ihyroid  >..  v.^,^     I  r-      — 

Infra  -  by  aid    br.  of  sup.  tfiyroLclA^j)L(jc,f[jcM. 

^nnrn  -h\rni ri  hr  ca..t^    L,,^,"j    \A 


-Descending palatine  A. 

"Anterior  br.  of  descending  palatine  A . 

,St}-lo-gluss//.vAl. 

^Palato  -glossusM. 
^Tonsillar  br  dorsalis  linguae  A . 


Ranine  A 


Supra- hyoid  br 
of '  Ungual  A. 


Stylo-hyoid  M.     Sublingual  A 


Artery  of  fraenum 
-Submental  A. 
(Jcrnn-hyoid  ?!. 
Cenio  fi\-o  -glossus  M. 


ARTERIES  OF  TONGUE  AND  TONSIL 
105 


DISSECTION  OF  THE  NECK.  107 

of  tlio  floor  of  the  triangle,  as  well  as  the  greater  part  of  the  floor  of  the  niuuth, 
will  1)0  completely  exposed. 

Tile  mylo-hyoid  is  a  triangularly  sliaped  muscle,  with  its  base  at  the  lower 
jaw  anil  its  apex  at  the  hyoitl  bone  ;  it  unites  along  the  middle  line  with  tlie  mylo- 
hyoid muscle  of  the  opposite  side.  It  is  sometimes  termed  the  diaphragm  of  the 
muuth,  or  the  vijuier  diaphi'agni.  It  arises  from  the  mylo-hyoiil  ridge  (inti'rnal 
oblicjue  line)  of  the  lower  jaw,  its  origin  extending  fnun  the  symphysis  as  far 
backward  as  the  last  molar  tooth.  The  posterior  fibers  are  inserted  into  the  body 
of  the  hyoid  bone ;  the  middle  and  anterior  fibers  into  the  median  fibrous  raphe, 
where  they  join  the  fibers  of  the  opposite  muscle.  Its  lower  or  cutaneous  surface 
has  the  anterior  belly  of  the  digastric  muscle,  the  supra-hyoid  aponeurosis,  the 
mvlo-hyoid  nerve  and  artery,  the  submental  vessels,  and  the  .submaxillary  glands 
in  relation  with  it.  The  duct  of  the  submaxillary  gland  winds  around  its  free 
posterior  border.  In  relation  with  its  deep  or  buccal  surface  are  the  genio-hyoid 
muscle,  part  of  the  hyo-glossus  and  stylo-glossus  muscles,  the  deep  pai't  of  the 
submaxillary  gland,  Wharton's  duct,  the  hypo-glossal  and  gustatory  nerves,  the 
submaxillary  ganglion,  the  sublingual  gland,  the  ranine  and  sublingual  arteries, 
and  the  mucous  membrane  of  the  mouth. 

Nerve  Supply. — From  the  mylo-hyoid  branch  of  the  inferior  dental  nerve. 
Blood  Supply.     From  the  submental  branch  of  the  facial  artery. 
Action. — When  both  muscles  act  conjointly  from  their  point  of  origin  they 
elevate  the  hyoid  bone,  the  larynx,  and   the  floor  of  the  mouth,  preparatory  to 
swallowing  ;  when  acting  from  their  hyoid  attachment  they  assist  in  depressing  the 
jaw  and  in  opening  the  mouth. 

Dissection. — Divide  the  facial  vessels  immediately  below  the  lower  jaw,  and 
displace  them  upward  with  the  superficial  jrart  of  the  submaxillary  gland,  leaving 
in  situ  the  deep  part  of  the  gland  which  turns  beneath  the  mylo-hyoid  muscle  and 
has  the  submaxillary  ganglion  in  contact  with  it.  Divide  the  small  vessels  and 
nerves  on  the  cutaneous  surface  of  the  mylo-hyoid  mnscle,  detaching  it  from  the 
lower  jaw  and  the  niylo-liy(ii<l  mu.scle  of  the  opjjosite  .side,  and  displace  it  down- 
ward. This  exposes  the  structures  in  relation  with  the  upper  surface  of  the  mylo- 
hyoid muscle. 

The  genio-hyoid  is  a  slender  muscle  which  arises  from  tlie  lower  of  the  two 
lateral  (genial)  tubercles  on  the  inner  aspect  of  the  symphysis  of  the  lower  jaw, 
and  is  inserted  into  the  middle  of  the  front  of  the  body  of  the  hyoid  bone.  It  is 
covered  by  tlie  mylo-hyoid  muscle,  rests  upon  the  genio-hyo-glos.sus  muscle,  and 
mesially  against  the  genio-hyoid  muscle  of  the  opposite  side. 
Nerve  Supply-. — From  the  hyi>o-glossal  nerve. 
Blood  Supply. — From  the  lingual  artery. 


108  SURGICAL  ANATOMY. 

Action. — It  raises  ami  advances  tlie.  liyoid  bone  ;  when  the  mouth  is  closed, 
acting  in  the  reverse  direction,  it  assists  in  depressing  the  lower  jaw  and  in  opening 
the  mouth.     It  may  be  inseparable  from  the  genio-hj'oid  muscle  of  the  other  side. 

Dissection. — The  lower  jaw  should  be  sawed  through  at  two  points — viz., 
immediately  in  advance  of  the  angle  and  at  the  symphysis ;  the  intervening  por- 
tion, carrying  with  it  the  mucous  membrane  of  the  mouth,  should  be  displaced 
upward,  and  fastened  with  hooks  or  with  a  stitch.  The  tongue  should  next  V)e 
drawn  out  of  the  mouth,  with  its  tip  ftistened  to  the  nose,  and  the  liyoid  bone 
drawn  downward  and  also  fixed  by  means  of  hooks,  thus  putting  the  muscular 
fibers  of  the  tongue  on  the  stretch.  All  the  fat  and  connective  tissue  having  been 
removed,  the  following  stractures  should  be  carefully  examined  :  The  hyo-glossus, 
stylo-glossus,  and  genio-hyo-glossus  muscles,  the  lingual  vein,  the  hypo-glossal 
nerve,  the  gustatory  or  lingual  nerve,  the  .submaxillary  ganglion,  Wharton's  duct, 
the  deep  portion  of  the  submaxillary  gland,  the  sublingual  gland,  the  ranine  and 
sublingual  artcrit'.s. 

The  hyo-glossus  is  a  thin,  flat,  sciuare-shaped  muscle,  arising  from  the  side 
of  the  body  of  the  hyoid  bone  and  from  its  greater  and  lesser  cornua.  It  is 
inserted  into  the  iiosterior  half  of  the  side  of  the  tongue  between  the  stylo-glossus 
and  lingualis  muscles.  Its  fibers  ascend  almost  perpendicularly  from  their  origin  to 
their  insertion,  and  mingle  with  the  fibers  of  the  palato-glossus  and  stylo-glossus 
muscles.  The  fibers  arising  from  the  body  of  the  hyoid  bone,  termed  the  basio- 
glossus,  pass  upward  and  backward,  and  overlap  those  which  arise  from  the  greater 
cornu,  termed  the  kerato-glosms,  which  are  directed  obliquely  forward.  Those  fibers 
which  arise  from  the  lesser  cornu  are  termed  the  chovdro-glossus,  and  are  separated 
from  the  remainder  of  the  muscle  by  a  few  filjers  of  the  genio-hyo-glossus  muscle ; 
they  are  covered  by  the  fibers  arising  from  the  body  of  the  hyoid  bone. 

Nerve  Supply. — From  the  hypo-glossal  nerve. 

Blood  Supply. — From  the  lingual  artery. 

Action. — It  draws  the  side  of  the  tongue  downward,  and  when  the  tongue  is 
protruded  it  draws  it  back  into  the  mouth. 

Relations  of  the  Hyo-glossus  Muscle. — Upon  the  outer  surface  of  the 
muscle  are  the  hypo-glossal  nerve  and  the  small  branch  which  ascends  to  the  stylo- 
glossus muscle,  the  gustatory  or  lingual  nerve,  the  loop  of  communication  between 
the  gustatory  and  hyo-glossal  nerves,  the  .submaxillary  ganglion,  the  submaxillary 
gland,  Wharton's  duct,  the  hyoid  brand i  df  the  lingual  artery,  the  lingual  vein,  the 
sublingual  gland,  the  posterior  belly  of  the  digastric,  the  .stylo-hyoid,  stylo-glossus, 
and  niyo-hyoid  naiscles.  Its  deep  surface  is  in  contact  with  the  genio-hyo-glossus, 
lingualis,  middle  constrictor  muscle  of  the  pharynx,  ])art  of  the  origin  of  the 
superior  constrictor  muscle,  the  lingual  artery,  the  glosso-pharyngeal  nerve,  and  the 


PLATE  XXIII. 


Stylo-glossus  m. 

Palatoglossus  m. 

Lymphoid  tissue  at  base  of  tongue 
Ciicumvallate  papillae 


Dorsum  of  tongue 


Hyoid  bone 


Mylo-hyoid  m. 
Genio-hyoid  m. 
Genlo-hyo-glossus  m. 


EXTRINSIC  MUSCLES  OF  TONGUE. 
109 


DISSECTION  OF  THE  NECK.  Ill 

stylo-hyoid  ligament.  At  the  jiosterior  lidnkT  of  tlir  liyo-glossus  niusclt'  niay  be 
seen  the  lingnal  artery,  the  .uln^^so-pliaryn^eal  nerve,  .■md  tlic  stylo-hyoid  ligament 
pas-sing  beneath  the  muscle.  At  the  anterior  border  may  be  seen  the  loop  ol'  com- 
munication between  the  gustatory  and  hypo-glossal  nerves,  tlie  brandies  of  which 
can  be  traced  to  the  under  surface  of  the  tongue ;  and  the  ranine  artery,  emcig- 
ing  from  l)eneath  the  anterior  liorder  of  the  hyo-glossus  muscle. 

The  stylo-glossus  muscle — the  smallest  of  tlie  three  muscles  which  arise 
from  the  styloid  process — has  its  origin  from  the  front  and  outer  side  of  that  process 
near  its  apex  and  from  the  stylo-maxillary  ligament.  Its  fibers  puss  downward  and 
forward,  and  then  run  almost  horizontally  to  be  inserted  along  the  side  of  the 
tongue,  superficial  to  the  hyo-glossus  muscle  and  as  far  forward  as  the  tip  of  that 
organ  ;  they  blend  with  the  fibers  of  the  lingualis  muscle.  Beneath  the  lower  jaw 
the  stylo-glossus  muscle  is  crossed  by  tlie  gustatory  or  lingual  nerve. 

Nerve  Supply. — From  the  hypo-glossal  nerve. 

Blood  Supply.— From  the  nmscular  branches  of  the  facial  artery. 

Action. — When  both  nmscles  act  together  they  raise  the  back  of  the  tongue 
toward  the  roof  of  the  mouth.  When  the  tongue  is  protruded,  they  draw  it  back 
into  tlu'  moutli.  They  also  draw  the  sides  of  the  tongue  uiiward,  thus  helping  to 
make  it  transversel}'  concave. 

The  genio-hyo-glossus  muscle,  the  largest  of  the  muscles  of  the  tongue,  is 
triangular  in  slia[)e,  with  its  a[)ex  attached  to  the  lower  jaw,  and  its  l)ase  to  the 
tongue  and  the  hyoid  bone.  It  arises  from  the  upper  genial  tubercle  on  the  inner 
aspect  of  the  symphysis  of  the  lower  jaw,  immediatelj'^  above  the  genio-hyoid 
muscle.  The  fibers  diverge  from  their  origin,  the  inferior  fibers  passing  dow  nward 
to  be  inserted  into  the  l)ody  of  the  hyoid  lione,  the  nnddle  fibers  into  the  side  of 
the  pharynx,  and  the  superior  fibers  into  the  tongue  from  the  root  to  the  tip.  In 
relation  with  the  external  surface  of  the  muscle  are  the  stylo-glossus,  h3'o-glossus, 
and  lingualis  muscles,  the  lingual  artery,  the  hypo-glossal  and  gustatory  nerves,  the 
sublingual  gland,  and  the  submaxillary  or  Wharton's  duct.  It  is  separated  from 
the  genio-hyo-glossus  muscle  of  the  opposite  side  by  the  filirous  septum, — the  srp- 
(>iin  lingua:', — wliich  extends  through  tlie  middle  of  the  tongue.  Below  it  is  the 
genio-hyoid  muscle. 

Nerve  Supply. — From  the  hypo-glossal  nerve. 

Blood  Supply. — From  the  lingual  artery. 

Action. — By  the  simultaneous  action  of  all  tlie  fibers  of  the  muscle  attached 
to  the  tongue  that  organ  is  depressed  and  its  upper  surface  grooved.  The  fibers 
inserted  near  the  base  of  the  tongue  protrude  it,  while  these  attached  near  the  tip 
retract  it  after  if  has  been  jirotruded.  The  inferior  fibers  aid  the  genio-hyoid  and 
anterior  belly  of   the   digastric  muscle  in  pulling  the  hyoid  bone  upward  and 


112  SURGICAL  ANATOMY. 

forward  ;  acting  from  below,  they  tend  to  depress  the  chin.  Contraction  of  tijis 
muscle  in  epileptic  convulsions  causes  the  tongue  to  proti'ude  from  the  mouth,  and 
it  may  thus  be  bitten.  In  certain  fractures  of  the  lower  jaw,  as  well  as  in  some 
operations  about  the  tongue  and  floor  of  the  mouth  in  which  the  origin  of  this 
muscle  is  detached,  the  tongue  has  a  tendency  to  fall  backward  over  the  superior 
aperture  of  the  larynx,  and  respiration  may  be  embarrassed.  During  anesthetiza- 
tion the  base  of  the  tongue  at  times  falls  Ijackward,  and  breathing  becomes 
labored  ;  by  carrying  the  angles  of  the  lower  jaw  forward,  the  genio-liyo-glossus 
muscles  are  made  to  pull  the  tongue  forward,  and  thus  to  relieve  the  difficulty. 
If  the  genio-hyo-glossus  muscle  of  one  side  is  paralyzed  and  the  patient  is  asked  to 
protrude  the  tongue,  the  sound  muscle  pulls  its  own  side  of  the  base  of  the  tongue 
forward,  whereas  the  other  side  is  not  acted  upon ;  the  tip  of  the  organ  will  con- 
sequently protrude  toward  the  paralyzed  side. 

The  lingual  vein  arises  near  the  tip  of  the  tongue,  where  it  is  also  known  as 
the  ranine  vein.  It  receives  a  branch  of  the  superior  thyroid  vein  and  the  vense 
comites  of  the  lingual  artery,  the  tributaries  of  which  correspond  to  the  branches 
of  the  lingual  artery.  It  accompanies  the  hypo-glossal  nerve  over  the  outer  surface 
of  the  hyo-glossus  muscle,  which  separates  it  from  the  lingual  artery.  It  passes 
beneath  the  stylo-hyoid  and  posterior  belly  of  the  digastric  muscle,  and  empties 
into  the  internal  jugular  or  facial  vein.  When  the  lingual  vein  empties  into  the 
internal  jugular  vein,  it  crosses  the  external  carotid  artery  at  about  the  level  of  the 
greater  cornu  of  the  hyoid  bone. 

The  hypo-glossal  nerve. — Its  course  as  far  as  the  point  where  it  passes 
beneath  the  posterior  border  of  the  mylo-hyoid  muscle  has  been  described.  In  the 
submaxillary  triangle  it  lies  on  the  hyo-glossus  muscle,  accompanied  by  the  lingual 
vein,  and  communicates  witli  the  gustatory  or  lingual  nerve  at  the  anterior  border 
of  that  muscle,  from  which  point  it  continues  forward  to  the  tip  of  the  tongue  in 
the  substance  of  the  genio-hyo-glossus  muscle. 

The  gustatory  or  lingual  nerve  is  a  branch  of  the  inferior  maxillary  division 
of  the  fifth  nerve,  and  for  some  little  distance  from  its  origin  it  lies  in  the  pterygo- 
maxillary  region.  This  portion  of  the  nerve  has  been  described  under  the  Dissec- 
tion of  the  Pterygo-maxillary  Region.  Passing  between  the  ramus  of  the  lower 
jaw  and  the  internal  pterygoid  muscle  it  leaves  the  pterygo-maxillary  region, 
inclines  forward  along  the  side  of  the  tongue,  and  runs  upon  the  superior  constrictor 
muscle  of  the  pharynx  and  between  the  stylo-glossus  muscle  and  the  deep  portion 
of  the  submaxillary  gland.  It  next  crosses  the  upper  part  of  the  hyo-glossus 
muscle  ami  ^\'harton's  duct,  whence  it  jiasses  between  the  mylo-hyoid  nniscle  and 
the  mucous  mend)rane  of  the  floor  of  the  mouth  along  the  side  of  the  tongue  to  its 
ti}).     Two  or  more  branches  connect  the  gustatory  nerve  with  the  submaxillary 


DISSECTION  OF  THE  NECK.  113 

ganglion  near  the  root  of  the  tongiu\  wliilo  near  the  anterior  horder  of  the  hyo- 
glossus  muscle  it  forms  a  loop  with  the  hypo-glossal  nerve. 

It  suiiplies  the  mucous  menihrane  of  the  mouth,  the  lower  gums,  and  the  sub- 
lingual and  submaxillary  glands,  and  gives  off  branches  which  ascend  through 
the  muscular  substance  of  the  tongue  to  the  tiliform  and  fungiform  papilltc.  The 
branches  to  the  sublingual  and  submaxillary  glands  contain  secreto-motor  fibers, 
which,  when  stimulated,  increase  the  secretion  of  these  glands.  The  lingual  is 
the  common  sensorj'  nerve  of  the  tongue,  and  contains  taste  fibers  foi'  the  anterior 
two-thirds  of  that  organ. 

The  submaxillary  ganglion  is  small,  and  is  situated  upon  the  hyo-glossus 
muscle,  between  the  gustatory  nerve  and  the  deep  portion  of  the  submaxillary 
gland  and  beneath  the  posterior  border  of  tiie  mylo-hyoid  muscle.  Like  the  other 
ganglia  of  the  head,  it  is  connected  with  the  branches  of  the  trifacial  nerve  and 
receives  filaments  of  communication  of  three  kinds — viz.,  motor,  sensorj^  and  sym- 
pathetic. Its  motor  root  arises  froni  the  facial  nerve  through  the  chorda  tj'mpani ; 
the  sensory  branches  are  derived  from  the  gustator}'  or  lingual  nerve  ;  its  connec- 
tion with  the  sympathetic  nerve  is  through  a  branch  which  comes  from  the  nervi 
molles  around  the  facial  arter}'.  Its  branches  of  distribution,  five  or  six  in 
number,  supply  the  mucous  membrane  of  the  floor  of  the  mouth,  and  the  sub- 
maxillary gland  and  its  duct. 

Wharton's  duct,  the  duct  of  the  submaxillary  gland,  is  about  two  inches 
long,  and  has  its  origin  in  the  deep  portion  of  the  gland.  It  winds  around  the 
posterior  or  free  border  of  the  mylo-hyoid  muscle,  then  lies  on  the  hyo-glossus 
muscle,  between  the  hypo-glossal  and  gustatory  nerves,  under  cover  of  the  mylo- 
hyoid muscle ;  thence  it  passes  forward  over  the  genio-hyo-glossus  muscle,  and 
beneath  the  gustatory  nerve  and  sublingual  gland,  terminating  in  a  constricted 
opening,  situated  on  a  small  papilla  in  the  floor  of  the  mouth  at  the  side  of  the 
lingual  frenum.  Near  its  termination  it  is  joined  by  one  of  the  ducts  of  the  sub- 
lingual gland — the  duct  of  Bartholin. 

The  submaxillary  gland. — The  deep  portion  of  the  submaxillary  gland  turns 
forward  around  the  posterior  or  free  border  of  the  mylo-hyoid  muscle,  lying 
between  it  and  the  hyo-glossus  muscle. 

The  sublingual  gland,  the  smallest  of  the  three  salivary  glands,  lies  upon  the 
mylo-hyoid  muscle  beneath  the  mucous  membrane  of  the  floor  of  the  mouth  at 
the  side  of  the  lingual  frenum,  where  it  produces  an  oblong  prominence.  It  is  in 
contact,  on  its  inner  side,  with  the  hyo-glossus,  genio-hyo-glossus,  and  stylo-glossus 
muscles,  the  gustatory  nerve,  and  the  duct  of  the  submaxillary  gland.  On  its 
outer  side  it  is  in  relation  with  the  sublingual  fossa  in  the  body  of  the  lower  jaw 
and  with  the  mylo-hyoid  muscle ;  behind,  with  the  deep  portion  of  the  submaxil- 

S_ii-8 


114  SURGICAL  ANATOMY. 

laiy  gland,  touching  the  other  sublingual  gland  in  the  mesial  plane.  It  measures 
about  one  and  one-half  inches  in  its  long  diameter,  and  weighs  about  one  dram. 
Its  ducts — dudi  Rivini — are  from  ten  to  twenty  in  number,  and  open  separately  on 
the  ridge  at  each  side  of  the  lingual  frenum,  with  the  exception  of  two  or  more 
which  join  to  form  the  dud  of  Bartholin,  \ih\ch.  opens  either  near  or  into  Wharton's 
duct. 

Blood  Supply. — From  the  lingual  and  suljmental  arteries. 

Nerve  Supply. — From  the  gustatory,  chorda  tympani,  and  sympathetic 
nerves. 

Obstruction  of  the  salivary  ducts. — The  duet  of  the  submaxillary  gland 
may  become  obstructed  by  a  calculus,  and  give  rise  to  a  hard  and  painful  swelling 
over  the  site  of  the  duct,  perceptible  through  the  submaxillary  triangle  and 
through  the  floor  of  the  mouth.  Obstruction  and  dilatation  of  one  of  the 
several  ducts  opening  at  the  side  of  the  lingual  frenum  will  occasion  a  cystic 
swelling  known  as  ranula ;  this  condition  may  also  be  due  to  an  obstructed  mucous 
follicle. 

Dissection. — Detach  the  hyo-glossus  muscle  from  the  hj^oid  bone  and  lift  it 
up,  Avhen  the  structures  in  relation  with  the  deep  surface  may  be  seen ;  these  are 
the  horizontal  portion,  and  the  commencement  of  the  ascending  portion,  of  the 
lingual  artery,  part  of  the  genio-hyo-glossus  muscle,  the  lingualis  muscle,  the 
origin  of  the  middle  constrictor  muscle  of  the  pharynx,  the  glosso-pharyngeal 
nerve,  and  the  stylo-hyoid  ligament. 

The  horizontal  or  second  portion  of  the  lingual  artery  rests  upon  the  middle 
constrictor  of  the  pharynx  and  the  genio-hyo-glossus  muscle,  below  the  level  of  the 
glosso-pharyngeal  nerve,  and  is  covered  by  the  tendon  of  the  digastric,  the  stylo- 
hyoid, and  the  hyo-glossus  muscle.  From  this  portion  the  dorsalis  linguse  artery  is 
given  off,  which  ascends  to  the  base  of  the  tongue  to  supply  the  mucous  membrane 
back  of  the  circumvallate  papillae,  the  tonsil,  and  the  soft  palate.  It  anastomoses 
with  the  dorsalis  linguae  of  the  opposite  side,  but  this  anastomosis  is  so  fine  that 
but  slight  bleeding  follows  severance  of  the  tongue  accurately  in  the  median  line. 

The  ascending  or  third  portion  of  the  lingual  artery  commences  beneath  the 
hyo-glossus  muscle.  It  rests  u]>on  the  genio-hyo-glossus,  and  passes  tortuously 
between  the  genio-hyo-glossus  and  the  lingualis  muscle  to  the  tip  of  the  tongue, 
being  covered  only  by  the  mucous  membrane  of  the  under  surface  of  this  organ. 
This  portion  gives  off  the  sublingual  artery  and  continues  as  the  ranine. 

The  ranine  artery,  the  continuation  of  tiie  lingual  artery,  passes  to  the  tip  of 
the  tongue  along  the  outer  side  of  the  genio-hyo-glossus  muscle,  running  between 
it  and  the  lingualis  muscle,  and  is  accompanied  by  the  ranine  vein  and  the  ter- 
minal portion  of  the  gustatory  nerve.     Near  the  tip  of  the  tongue  it  anastomo.ses 


DISSECTION  OF  THE  NECK.  115 

witli  tlic  ranine  artery  ol"  Hk'  opposite  side,  and  on  its  way  supplies  the  adjacrnt 
musi-k'S  and  nmeous  nicnilirane. 

Tlie  sublingual  artery,  smaller  than  the  ranine,  arises  near  the  aulerinr  hor- 
der  of  the  hyo-glossus  muscle,  and  runs  outward  and  forward  over  the  oral  surfac-e 
of  the  mylo-hyoid  muscle  to  reach  the  sublingual  gland.  It  supplies  the  sublin- 
gual gland,  the  mylo-hyoid  muscle,  the  mucous  membrane  of  the  floor  of  the 
mouth,  and  the  gums.  It  anastomoses  with  the  opposite  sublingual  artery,  and 
with  the  submental  branch  of  the  facial  artery,  after  having  perforated  the  mylo- 
hyoid muscle. 

The  artery  of  the  frenum  is  usually  a  branch  of  the  sublingual  artery.  It  is 
sometimes  wounded  in  operating  for  "  tongue  tie."  The  best  way  to  divide  the 
lingual  frenum  so  as  to  avoid  wounding  the  vessel  is  to  place  the  child  upon  its 
back  in  the  mother's  lap,  and,  with  the  head  held  tightly  between  the  knees  of  the 
operator,  to  engage  the  frenum  in  the  slot  of  a  grooved  director,  by  means  of  which 
the  point  of  the  tongue  can  be  held  up.  The  frenum  is  thus  made  tense,  and  at 
its  attachment  to  the  lower  jaw  is  then  simply  nicked  with  a  pair  of  blunt  scissors, 
after  which  any  additional  separation  which  may  be  required  can  be  done  with 
the  finger  nail. 

The  stylo-pharyngeus  muscle,  long  and  slender,  arises  from  the  inner  side 
of  the  base  of  the  styloid  process,  and  is  the  longest  of  the  three  muscles  arising 
therefrom.  It  passes  downward  and  forward,  and  disappears  between  the  middle 
and  superior  constrictor  muscles  of  the  pharynx.  Some  of  its  fibers  join  the  palato- 
pharyngeus  muscle,  to  be  inserted  into  the  posterior  border  of  the  thyroid  cartilage. 
The  remaining  fibers  become  connected  with  the  fibers  of  the  constrictor  muscles 
of  the  pharynx.  Running  along  its  outer  side  is  the  glosso-pharyngoal  nerve.  In 
order  to  reach  the  tongue,  to  wdiich  it  is  partly  distributed,  the  nerve  passes  over 
the  muscle,  supplying  it  with  twigs. 

The  stylo-hyoid  ligament  is  a  fibrous  cord  which  passes  from  the  tip  of  the 
styloid  process  to  the  lesser  cornu  of  the  hyoid  bone.  It  maj^  be  seen  lying  near 
the  anterior  border  of  the  stylo-pharyngeus  muscle,  and  passing  beneath  the  hyo- 
glossus  muscle  to  the  lesser  cornu  of  the  hyoid  bone.  It  is  the  continuation  of  the 
styloid  process ;  it  maj'  contain  nodules  of  cartilage,  and  may  be  largely  ossified, 
forming  an  unusually  long  styloid  process. 

Dissection. — Cut  off  the  styloid  process  at  its  base,  and  reflect  it  downward 
with  the  attached  muscles  and  the  stylo-hyoid  ligament. 

The  glosso-pharyngeal  nerve. — Running  along  the  posterior  border  of  the 
stylo-pharyngeus  muscle,  and  crossing  in  front  of  it,  is  the  glosso-pharyngeal  nerve. 
It  cur\'es  upon  the  side  of  the  neck,  the  convexity  being  directed  downward  and 
backward  ;    it  resembles  in  this  respect  the  hypo-glos.sal  and  superior   laryngeal 


116  SURGICAL  ANATOMY. 

nerves.  The  principal  landniarlv  for  findinp;  tliis  nerve  is  the  stylo-pharyngeus 
muscle,  around  M'hieh  it  curves,  licyund  the  stylo-pharyngeus  muscle  the  glosso- 
pharyngeal nerve  lies  on  the  middle  constrictor  muscle  of  the  pharynx.  The  ter- 
minal portion  of  the  nerve  lies  beneath  the  hyo-glossus  muscle,  where  it  divides 
into  two  terminal  lingual  branches,  one  supplying  the  mucous  membrane  covering 
the  posterior  third  of  the  dorsum  of  the  tongue,  and  the  other  the  mucous  mem- 
brane of  the  side  of  the  tongue,  inosculating  with  the  lingual  nerve.  The  glosso- 
pharyngeal is  a  nerve  of  motion,  sensation,  and  special  sense  (taste) :  of  motion,  to 
the  muscles  of  the  j^harynx  ;  of  sensation,  to  the  mucous  membrane  of  the  fauces, 
tonsil,  and  pharynx  ;  and  of  taste,  to  the  base  of  the  tongue  and  the  fauces. 

It  leaves  the  cranial  cavity  by  way  of  the  middle  compartment  of  the  jugular 
foramen,  clothed  by  a  separate  sheath  of  the  dura  mater,  and  lying  in  advance  of, 
and  a  little  internal  to,  the  pneumogastric  and  spinal  accessorj'  nerves.  Having 
made  its  exit  from  the  foramen,  it  descends  between  the  internal  jugular  vein  and 
the  internal  carotid  artery,  crosses  over  the  latter  vessel  obliquelj',  and  passes 
beneath  the  styloid  process  and  the  muscles  arising  therefrom,  to  reach  the  posterior 
border  of  the  stylo-pharyngeus  muscle,  as  previously  described. 

Upon  the  trunk  of  the  nerve  in  the  jugular  foramen  are  two  ganglia :  an 
upper,  the  jugular,  and  a  lower,  the  petrous.  The  former  is  inconstant,  and  lioth 
are  considered  analogous  to  the  ganglia  on  the  posterior  roots  of  the  spinal  nerves. 
At  the  petrous  ganglion  (ganglion  of  Andersch),  the  glosso-pharyngeal  nerve  is  con- 
nected with  the  pneumogastric  and  sympathetic  nerves  by  communicating  branches. 
The  branches  of  the  glosso-pharyngeal  nerve,  other  than  the  terminal  lingual  and 
the  communicating,  are  the  meningeal,  tympanic,  carotid,  pharyngeal,  muscular, 
and  tonsillar. 

The  meningeal  branches  arise  within  the  cranial  cavity,  and  are  distributed  to 
the  pia  mater  and  arachnoid. 

The  tympanic  branch  {Jacobson^s  nerve)  arises  from  the  petrous  ganglion,  and 
passes  to  the  inner  wall  of  the  tympanum  through  a  bony  canal  (the  tympanic 
canaliculus)  the  orifice  of  which  is  situated  upon  the  ridge  of  bone  between  the 
carotid  canal  and  the  jugular  fossa.  It  ramifies  ujion  the  promontory  of  the  tym- 
panum, forming  the  tympanic  plexus,  which  supjdies  branches  to  the  round  and 
oval  windows,  and  to  the  Eustachian  tube,  and  communicates  with  the  carotid 
plexus  and  with  the  great  and  small  superficial  petrosal  nerves. 

The  carotid  branches  surround  the  cervical  portion  of  the  internal  carotid 
artery,  and  communicate  with  the  pneumogastric  and  sympathetic  nerves. 

Tiie  pharyngeal  branches,  three  or  four  in  nuinlicr,  join  l>rnnehos  from  the 
pneumogastric,  superior  laryngeal,  and  sympathetic  nerves,  and  from  the  pharyn- 
geal plcms,  which  supplies  the  pharynx. 


PLATE  XXIV. 


Anterior  belly  of  digastric  m.  Inferior  labial  v 


Mylo-hyoid  m 


Sterno-hyoid  m. 


Omo-hyoid  m 


Sterno-thyroid  m L 


Sterno-mastoid  m 

Sterno-thyroid  m.' 


// 


Infrahyoid  v. 


Communicating  vein 
from  submental  or 
facial  vem 


Anterior  jugular  v. 
Communicating  br.  between  anterior  jugular  veins 


SUPERFICIAL  STRUCTURES  NEAR  MEDIAN  LINE  OF  NECK. 
117 


DISSECTION  OF  THE  NECK.  110 

The  muscular  branch  .supiilie.s  the  stylo-pharyngevis  muscle. 

The  tonsillar  branches  arise  under  tlie  hyo-glossus  muscle,  and  are  distributed 
to  and  around  the  tonsils,  forniin<^  a  plexus  from  whieh  1)rauehes  to  the  fauces  and 
soft  palate  are  derived. 

The  communicating  branches  ai'ise  from  the  petrous  ganglion,  as  stated,  and 
run  to  the  superior  cervical  ganglion  ;  to  the  auricular  branch  of  the  pneumogas- 
trie,  forming  a  loop;  an  inconstant  l)raneli  to  the  ganglion  of  (lie  root  of  the  pncu- 
mogastric  nerve  ;  and  ont^  fruni  the  nerve  just  below  the  ganglion,  to  join  the 
lingual  branch  of  the  facial  nerve. 

Tlie  lingual  branches  proceed  from  the  end  of  the  glosso-pharyngeal  nerve,  and 
are,  therefore,  its  terminal  tilaments.  They  are  distrilmted  mainly  to  the  circum- 
vallate  papillte,  while  some  filaments  supply  the  follicular  glands  of  the  tongue 
and  the  front  of  the  epiglottis.  Others  inosculate  around  the  foramen  ctecum  with 
those  of  the  same  nerve  of  the  opposite  side. 

The  Internal  Carotid  Artery,  tlie  larger  of  the  two  terminal  divisions  of  the 
common  carotid,  ascends  perpendicularly  b}'  the  side  of  the  pharynx  to  the  base 
of  the  skull,  where  it  enters  the  carotid  canal,  in  the  petrous  portion  of  the 
temporal  bone.  It  lies  at  first  on  the  outer  side  of  the  external  carotid  artery,  and 
then  lieluml  it.  At  its  origin  it  is  more  superficial  than  elsewhere,  and  lies  in  tlie 
superior  carotid  triangle  ;  but  as  it  ascends  it  lies  more  deeply,  passing  beneatli  the 
parotid  gland,  the  posterior  belly  of  the  digastric  muscle,  styloid  process,  stylo- 
pharyngeus  and  stylo-hyoid  muscles.  It  is  crossed  by  the  hypo-glossal  and  glos.so- 
pharyngeal  nerves,  and  the  occipital  and  posterior  auricular  arteries.  Externally 
it  is  in  close  relation  with  the  inti'rnal  jugular  vein  and  the  pneumogastric  nci-ve, 
and  near  the  ba.se  of  the  skull  with  the  glosso-pharyngeal,  hypo-glossal,  and  spinal 
accessory  nerves ;  behind,  with  the  rectus  capitis  anticus  major  muscle,  the  superior 
ganglion  of  the  sympathetic  nerve,  and  the  superior  laryngeal  nerve ;  internally, 
with  the  pharynx,  the  tonsil,  and  the  ascending  pharyngeal  artery ;  in  front  it  is 
covered  by  the  skin,  fasciae,  parotid  gland,  and  .the  structures  which  pass  between 
it  and  tlie  external  carotid  artery — tlie  stylo-glo.s.sus  and  stylo-pharyngeus  niuselcs, 
the  glosso-pharyngeal  nerve,  and  the  stylo-hyoid  ligament. 

Dissection. — The  deep  fascia  upon  each  .side  of  the  median  line  of  the  neck 
having  been  removed,  the  anterior  belly  of  the  orao-hyoid,  the  sterno-hyoid, 
sterno-thyroiil,  and  thyro-hyoid  muscles  will  be  exposed. 

The  omo-hyoid  muscle  consists  of  two  bellies,  an  anterior  and  a  posterior, 
connected  by  an  intervening  tendon.  The  anterior  belly,  which  is  exposed  in 
this  dissection,  commences  at  the  tendon  intervening  between  the  two  bellies  of 
the  muscle  beneath  the  sterno-mastoid  muscle  and  in  front  of  the  carotid  sheath, 
on  a  level  with  the  cricoid  cartilage.     It  passes  upward  along  the  outer  border  of 


120  SURGICAL  ANATOMY. 

the  sterno-hyoid  and  over  the  sterno-thyroid  and  thyro-hyoid  muscles,  to  be 
inserted  into  the  lower  border  of  the  body  of  the  hyoid  bone  external  to  the 
sterno-hyoid  muscle.  It  lies  beneath  the  superficial  layer  of  the  deep  fascia  and 
sterno-mastoid  muscle,  and  in  front  of  the  thyro-hyoid  and  sterno-thyroid  muscles 
and  the  carotid  sheath.  It  may  be  absent  or  double,  or  may  blend  with  the  adja- 
cent sterno-hyoid  muscle ;  occasionally  it  receives  an  accessory  slip  from  the  manu- 
brium sterni,  or  sends  one  to  the  lower  jaw. 

The  posterior  belly  of  the  muscle  has  already  been  seen  crossing  the  posterior 
triangle  just  above  the  clavicle,  and  dividing  it  into  the  occipital  and  subclavian 
triangles.  It  arises  from  the  upper  border  of  the  scapula,  behind  the  supra-scapular 
notch,  and  from  the  transverse  ligament,  and  may  have  an  additional  origin  from 
the  upper  surface  of  the  middle  third  of  the  clavicle.  It  terminates  in  the  tendon 
of  the  omo-hyoid  muscle  which  crosses  the  carotid  sheath.  It  is  covered  by  the 
superficial  layer  of  the  deep  fascia,  trapezius  muscle,  clavicle,  subclavius  muscle, 
sterno-mastoid  muscle,  external  jugular  vein,  and  the  descending  superficial 
branches  of  the  cervical  plexus  of  nerves.  It  pas.ses  over  the  first  digitation  of  the 
serratus  magnus  muscle  and  third  part  of  the  subclavian  artery,  the  transversalis 
colli  and  supra-scapular  arteries,  the  supra-scapular  nerve,  the  cervical  trunks  of 
the  brachial  plexus,  the  scaleni  muscles,  the  prevertebral  fascia,  and  the  carotid 
sheath.  The  intervening  tendon  is  bound  down  by  a  process  of  the  deep  fascia, 
attached  to  the  clavicle  and  first  rib. 

Action. — It  draws  the  hyoid  bone  downward  and  assists  in  making  tense 
the  lower  portion  of  the  deep  cervical  fascia,  thus  diminishing  the  atmo.spheric 
pressure  upon  the  large  veins  at  the  root  of  the  neck  and  favoring  the  return  cir- 
culation. 

Nkrve  Supply. — It  is  supplied  by  the  descendens  hypoglossi  and  the  com- 
municantcs  hypoglossi  nerves. 

The  sterno-hyoid  muscle  arises  from  the  posterior  surface  of  the  upper  part 
of  the  manul)rium  sterni,  the  posterior  sterno-clavicular  ligament,  and  the  posterior 
surface  of  the  inner  extremity  of  the  clavicle.  Its  fibers  pass  upward  and  inward 
to  be  inserted  into  the  lower  border  of  the  body  of  the  hyoid  bone.  It  has,  at 
times,  a  tendinous  intersection  in  its  lower  part.  It  lies  beneath  the  skin  and 
fascia),  anterior  jugular  vein,  sterno-mastoid  muscle,  sterno-clavicular  joint,  and  the 
manubrium  sterni ;  in  front  of  the  sterno-thyroid,  thyro-hyoid,  and  crico-thyroid 
muscles,  the  thyroid  and  cricoid  cartilages,  the  thyro-hyoid  and  crico-thyroid  mem- 
bi'aiies,  the  pretracheal  fascia,  trachea,  isthmus  of  the  thyroid  body,  and  inferior 
thyroid  veins. 

Nerve  Supply. — From  the  loop  between  the  descendens  and  communicantes 
hypoglossi  nerves. 


DISSECTION  OF  THE  NECK.  121 

Blood  Supply. — Fnun  ln-aiKluvs  i)f'  the  superior  thyroid  artery. 

Action. — It  draws  the  iiyuid  l)oiie  downward,  as  al'ter  swallowinp,-.  In  laliored 
respiration  it  will  aet  as  an  elevator  of  the  stermini,  heing  an  accessory  nuisele  of 
respiration. 

The  sterno-thyroid  muscle  is  wider  and  shorter  than  the  sternodiyoid  muscle, 
beneath  which  it  lies.  It  arises  from  the  posterior  sui'face  of  the  ui)per  part  of  the 
manubrium  sterni  and  the  cartilage  of  the  first  rib,  below,  and  internal  to  the 
sterno-hyoid  muscle.  Its  fibers  pass  upward  and  outwaid,  and  are  inserted  into  the 
obli(iue  line  on  the  side  of  the  thyroid  cartilage,  where  it  is  continuous  with  the 
thyro-hyoid  muscle.  In  the  inferior  carotid  triangle  the  outer  border  of  the 
muscle  partly  overlaps  the  sheath  of  the  common  carotid  artery.  It  lies  beneath 
the  skin  and  fascia3,  the  nianubiium  sterni,  anterior  jugular  vein,  sterno-mastoid, 
sterno-hyoid,  and  anterior  l)elly  of  the  omo-hyoid  muscle,  and  in  front  of  the 
thyroid  and  cricoid  cartilages,  the  crico-thyroid  muscle,  the  inferior  constrictor 
muscle  of  the  pharynx,  thyroid  gland,  inferior  thyroid  veins,  pretracheal  fascia, 
trachea,  common  carotid  artery,  and  left  innominate  vein.  This  muscle  may  be 
absent  or  double. 

Nerve  Supply. — From  the  ansa  hvpoglossi. 

Action. — It  draws  the  thyroid  cartilage  downward,  as  after  swallowing,  and 
assists  the  crico-thyi'oid  muscle  in  making  tense  the  vocal  cords,  by  drawing  the 
thyroid  cartilage  downward  and  forward.     It  is  an  accessory  muscle  of  respiration. 

The  interspace  between  the  internal  borders  of  the  sterno-hyoid  muscles  is 
wider  at  the  sternum  than  at  the  hyoid  bone,  while  the  interspace  between  the 
inner  margins  of  the  sterno-thyroid  muscles  is  wider  above  than  at  the  sternum  ;  a 
lozenge-shaped  intermuscular  space  is  thus  formed. 

The  thyro-hyoid  muscle,  apparently  an  extension  of  the  sterno-thyroid  mus- 
cle, arises  from  the  obIi(iue  line  on  the  side  of  the  thyroid  cartilage.  Its  fibers 
ascend  and  are  inserted  into  tlie  lower  border  of  the  body  and  the  inner  half  of 
the  greater  cornu  of  the  hj'oid  bone.  The  sterno-mastoid,  sterno-hyoid,  and  the  an- 
terior 1  jelly  of  the  omo-hyoid  muscle  pass  over  the  outer  surface  of  the  thyro-hyoid 
muscle  ;  the  superior  laryngeal  vessels  and  nerve,  the  thyro-hyoid  membrane,  bursa, 
and  the  thyroid  cartilage  lie  beneath  it. 

Nerve  Supply. — From  the  hypo-glossal  nerve. 

Blood  Supply. — From  the  hyoid,  the  sterno-mastoid,  and  the  crico-thyroid 
branches  of  the  superior  thyroid  artery,  and  the  liyoid  branch  of  the  lingual  artery. 

Action. — It  raises  the  thyroid  cartilage  toward  the  hyoid  bone  preparatory  to 
swallowing,  and  in  conjunction  with  the  sterno-thyroid  muscle  it  dei)resses  the 
hyoid  bone  and  larynx. 

Dissection. — Divide    the   sterno-hyoid  and  sterno-thvroid    muscles    at    their 


122  SURGICAL  ANATOMY. 

middle,  and  reflect  them  upward  and  downward.  This  exposes,  from  above  down- 
ward, the  thyro-hyoid  membrane,  pierced  upon  each  side  by  the  internal  branch 
of  the  superior  laryngeal  nerve  and  the  superior  laryngeal  artery  ;  the  thyroid 
cartilage  ;  the  crico-thyroid  membrane,  upon  which  are  the  crico-thyroid  arteries  ; 
the  cricoid  cartilage,  partly  concealed  by  the  crico-thyroid  muscles  ;  the  first,  and 
at  times  the  second,  ring  of  the  trachea  ;  the  thyroid  gland,  its  middle  portion,  or 
isthmus  connecting  the  two  lateral  lobes  ;  the  trachea,  covered  by  a  plexus  of  veins 
formed  by  the  anastomoses  of  the  inferior  thyroid  veins  ;  the  middle  thyroid  artery, 
when  present,  and  the  pretracheal  fascia. 

The  Thyroid  Gland  or  Body,  a  ductle.ss  and  very  vascular  structure,  is  situated 
on  the  front  and  sides  of  the  upper  part  of  the  trachea,  and  the  sides  of  the  lower 
part  of  the  larynx.  It  con,sists  of  two  lateral  lobes  and  a  middle  lobe,  or  isthmus, 
and  weighs  from  one  to  two  ounces.  Each  lateral  lobe  is  about  two  inches  in  length, 
one  and  one-fourth  inches  in  breadth,  and  three-fourths  of  an  inch  in  thickness. 
Each  lateral  lobe  is  pyriform  or  cone-shaped,  the  apex  directed  upward  ;  it  extends 
from  the  fifth  or  sixth  ring  of  the  trachea  to  the  laiddle  of  the  side  of  the  thyroid 
cartilage.  It  is  convex  anteriorly,  and  is  situated  between  the  trachea  and  the 
sheath  of  the  common  carotid  artery,  and  is  covered  anteriorly  by  the  sterno-hyoid, 
the  sterno-thyroid,  and  the  anterior  belly  of  tlie  omo-hyoid  muscle.  Its  deej"!  sur- 
faces is  concave,  and  in  contact  with  the  trachea,  larynx,  pharynx,  esophagus,  infe- 
rior thyroid  artery,  and  recurrent  laryngeal  nerve.  From  its  upper  part,  and  most 
commonly  from  the  left  lobe,  a  conic  piece,  called  the  pyramid,  at  times  ascends 
toward  the  hyoid  bone,  to  which  it  is  attached  by  a  fibrous  band  in  front  of  the 
thyro-hyoid  membrane  ;  this  part  is  at  times  attached  to  the  hyoid  bone  by  a 
sli})  of  muscle,  the  levator  glandulse  thyroideas  of  Soemmering.  The  middle  lobe,  or 
isthmus,  is  about  one-half  of  an  inch  in  depth,  and  rests  upon  the  second  and 
third  rings  of  the  trachea.  The  isthmus  varies  much  in  its  dimensions,  and  is 
sometimes  absent.  There  is  a  space  between  the  upper  border  of  the  middle  lobe, 
or  isthmus,  and  the  cricoid  cartilage,  where  the  trachea  is  not  covered  b)^  the 
gland  ;  this  portion  of  the  trachea  is  opened  in  the  high  operation  of  tracheotomy. 
To  perform  this  operation  when  the  space  is  covered  by  the  middle  lobe,  it  is  nec- 
essary either  to  displace  the  lobe  downward  or  pass  two  ligatures  around  it  and 
divide  it  between  them.  In  some  instances,  however,  the  width  of  the  middle  lobe, 
or  isthnms,  is  so  great  that  it  covers  the  trachea  almost  to  the  sternum.  The  low 
operation  of  tracheotomy  is  performed  below  the  isthmus  of  the  gland.  That  this 
operation  is  tlic  more  difficult  of  the  two  will  be  seen  at  a  glance  in  the  dissected 
neck  ;  this  is  due  to  tin;  increasing  depth  of  tlie  trnciu^a  as  it  approaches  the  ster- 
num, and  the  presence  of  the  tliyroid  plexus  of  veins  in  front  of  this  part  of  the 
trachea.     An  abnormally  high  position  of  the  large  vessels  at  the  root  of  the  neck 


PLATE  XXV. 


Greater  cornu  of  hyoid  bone 

Lesser  cornu  of  hyoid  bone 
Lateral  portion  of  thyro-hyoid  membrane 


Internal  laryngeal  n 
Superior  laryngeal  a 


Epiglottis 


^r*^—*    — Hyoid  bone 


Thyroid  cartilage 


Crico-thyroid  membrane 


Crico-thyroid  m I  \<    \^ 

l.atoral  lobe  of  thyroid  gland       ^  ^J 

Trachea ffil  {■ 

Isthmus  of  thyroid  gland 


Central  portion  of  thyro-hyoid 

membrane 


nferior  constrictor  m. 
of  pharynx 


uperior  thyroid  a. 

ico-thyroid  a. 

ator  glandulae  thyroideae 

cold  cartilage 


nferior  thyroid  veins 


THYROID   BODY. 
123 


DISSECriOX  OF  THE  NECK.  125 

woulil  ailil  to  the  difficulty  ami  ihingcr  of  the  low  operation.  The  tliyroid  .silaiid 
is  closely  atlaclicd  l>y  ari'olar  tissue  to  the  sides  of  the  ti'achea  ami  tiie  ericoiil  :nid 
thyroid  curtilages.  During  deglutition  it  rises  and  falls  witii  the  larynx — a  fact 
of  the  utmost  value  in  the  ditt'erential  diagnosis  between  cervical  tumors  and 
enlargement  of  this  gland.  It  varies  in  size  in  different  individuals  and  at  differ- 
ent periods  of  life,  being  relatively  larger  in  children  ami  in  females.  It  often 
enlarges  during  menstruation,  owing  to  increased  distention  of  the  hlood  vessels. 
The  right  lobe  is  larger  than  the  left.  In  old  age  the  gland  decreases  in  size, 
becomes  firmer,  and  at  times  contains  calcareous  substances.  AV'hen  enlarged,  it 
may  displace  and  compress  the  trachea,  especially  if  the  enlargement  take  place 
rapidly,  the  body  of  the  gland  being  held  down  by  the  sterno-thyroid  and  omo- 
hyoid muscles  ;  or  it  may  displace  the  great  vessels  of  the  neck  laterally,  so  that  the 
connnon  carotid  artery  may  be  felt  pulsating  at  the  outer  border  of  the  sterno- 
mastoid  muscle.  Venous  engorgement  may  also  ensue,  and  the  recurrent  laryngeal 
nerve  may  suffer  from  the  pressure  of  an  enlarged  thyroid  gland.  Bonnett  has 
practised  subcutaneous  section  of  the  muscles  in  some  cases  of  dyspnea  caused  by  a 
rapidly  growing  bronchocele  (enlarged  thyroid  gland).  Sir  Duncan  Gibb,  on  the 
other  hand,  because  of  the  fact  that  the  isthmus,  or  middle  lobe,  binds  together  the 
enlarging  lateral  lobes  of  a  bronchocele,  proposed  to  divide  the  isthmus  in  cases 
where  dyspnea  resulted.  He  performed  this  operation  several  times,  great  relief  to 
the  patient  ensuing.  As  the  lateral  borders  of  the  thyroid  gland  are  in  contact  with 
the  sheath  of  the  common  carotid  artery,  it  follows  that  the  gland,  when  enlarged, 
may  readily  receive  transmitted  pulsations  from  that  vessel.  An  error  is  occasion- 
ally made  by  mistaking  a  pulsating  goiter  for  aneurysm  of  the  common  carotid 
artery. 

The  median  lobe  of  the  thyroid  gland  is  developed  as  a  downgrowth  of  the 
epithelium  from  the  posterior  part  of  the  tongue  ;  the  site  from  which  this  starts  is 
indicated  in  the  adult  by  the  foramen  caecum  of  the  tongue.  The  canal  thus 
formed  is  known  as  the  thyro-glossal  duct,  or  canal  of  His.  Its  walls  normally 
disappear,  but  remains  of  them  are  frequently  found  in  the  j)yraniidal  jtrocess  of 
the  thyroid  gland.  Accessory  thyroid  glands,  occurring  near  the  median  line  of 
the  neck,  in  the  vicinity  of  the  hyoid  bone,  and  elsewhere  in  the  neck,  are  regarded 
as  being  formed  by  division  of  the  pyramidal  process.  Furthermore,  certain 
cystic  tumors  at  the  base  of  the  tongue  and  in  the  median  line  of  the  neck,  as  well 
as  the  rare  cases  of  median  cervical  fistula,  result  from  incomplete  obliteration  of 
the  thyro-glossal  duct. 

The  deep  surface  of  the  thyroid  gland  being  in  relation  with  the  lower  part  of 
the  pharynx  and  the  upper  part  of  the  esophagus,  the  difficulty  in  swallowing  often 
observed  in  bronchocele  is  explained  by  the  direct  pressure,  and  the  interference 


126  SURGICAL  ANATOMY. 

witli  the  movements  of  tlie  larynx.  luilargenient  of  the  left  lohe  of  the  gland 
is  more  likely  to  occasion  difficulty  in  swallowing  than  a  similar  condition  on  the 
right  side,  owing  to  the  inclination  of  the  esoj)hagus  toward  the  left.  In  a  case 
mentioned  by  Allan  Burns,  the  isthmus  was  located  between  the  trachea  and  the 
esophagus.  It  is  very  evident  that  enlargement  of  this  portion  of  the  gland  hold- 
ing such  abnormal  relation  would  occasion  great  difficulty  in  swallowing.  The 
author  has  seen  a  case  of  goiter  in  which  the  esophagus  was  so  nearly  occluded  that 
the  patient,  an  old  woman,  was  no  longer  able  to  swallow  liquids.  Atrophy  of 
the  thyroid  gland,  or  its  destruction  by  disease,  is  apt  to  be  followed  by  the  condi- 
tion known  as  myxedema.  Absence  of  the  thyroid  gland  in  children  causes 
cretinism  and  idiocy. 

The  arteries  of  the  thyroid  gland — two  on  each  side — are  the  superior  and 
inferior  thyroid.  The  superior  thyroid,  a  branch  of  the  external  carotid  artery, 
ramifies  chiefly  upon  the  anterior  aspect  of  the  gland,  while  the  inferior 
thyroid,  a  branch  of  the  thyroid  axis,  enters  the  under  and  inner  surface  of  the 
lateral  lobe  of  the  gland.  A  very  free  anastomosis  is  established  between  these 
vessels,  which  form  a  complete  network  around  the  acini  in  the  substance  of  the 
gland.  Occasionally  there  is  a  middle  thyroid  artery  (thyroidea3  ima),  a  branch  of 
the  innominate  artery  or  arch  of  the  aorta,  which  ascends  in  front  of  the  trachea 
and  enters  the  isthmus  of  the  gland. 

The  thyroid  gland  is  surrounded  by  a  thin,  dense,  fibrous  capsule,  which 
is  derived  from  the  pretracheal  fascia  and  sends  processes  into  the  interior  which 
separate  the  substance  into  lobules  of  varying  form  and  size.  The  vesicles  com- 
posing these  lobules  are  lined  by  a  single  layer  of  columnar  epithelium  and  contain 
a  colloid  substance.     Increase  of  this  colloid  substance  constitutes  a  form  of  goiter. 

The  nerves  of  the  thyroid  gland  are  derived  from  the  middle  and  lower 
cervical  sympathetic  ganglia,  and  accompany  the  inferior  thyroid  artery. 

The  thyroid  veins,  three  on  each  side,  are  the  superior,  the  middle,  and  the 
inferior  thyroid.  The  superior  and  middle  thyroid  veins  cross  in  front  of  the 
common  carotid  artery,  emptying  into  the  internal  jugular  vein.  The  inferior 
thyroid  veins  descend  on  the  trachea,  form  a  plexus  in  front  of  the  pretracheal 
fa.scia,  and  behind  the  sterno-thyroid  muscles,  and  empty  into  the  left  innominate 
vein.  The  numerous  and  large  lymphatics  pass  to  the  lymph  trunks  at  the  root 
of  the  neck.  In  some  cases  these  lymphatics  have  been  found  to  contain  colloid 
substance,  giving  rise  to  the  supposition  that  they  act  as  ducts  of  the  gland. 

Thyroidectomy. — In  the  operation  of  removal  of  half  of  the  thyroid  gland 
in  eitlicr  l)ilatcra!  nr  unila1ci-al  goiter  (l)ronch<:>ccle)  the  incision  may  be  made 
parallel  with  tlic  anterior  l)order  of  tlie  sterno-mastoid  muscle,  or  a  transverse 
curved  incision,  concave  upward,  may  be  carried  over  the  most  ])roniinent  portion 


DISSECTIOX  OF  THE  NECK.  127 

of  tho  tumor.  The  gland  being  exposed,  the  superior  and  inferior  thyroid  arteries 
shoidd  be  carefully  freed,  and  then  secured  and  divided  between  ligatures.  In  ex- 
posing the  inferior  thyroid  artery  preparatory  to  severing  it,  and  in  freeing  the  lower 
end  of  the  lateral  lobe  of  the  gland  behind,  care  must  be  exercised  to  avoid  injuring 
the  recurrent  laryngeal  nerve.  After  attempts  to  cure  a  unilateral  goiter  by  the 
injection  of  tincture  of  iodin  or  by  electro-puncture  have  ffiiled,  the  inflammation 
consequeM  upon  either  form  of  treatment  may  result  in  binding  the  gland  tightly 
to  the  carotid  sheath,  or  perhaps  to  the  wall  of  the  internal  jugular  vein.  Under 
these  circumstances  dis.secting  it  loose,  in  attempted  removal  of  the  goiter,  will  be 
attended  by  risk  of  tearing  the  vein.  Where  much  pei'iglandular  inflammation 
has  occurred,  the  recurrent  laryngeal  nerve  may  be  involved  in  the  deposit  of 
exudate,  this  condition  giving  rise  to  aj^honia,  which  is  likely  to  be  permanent 
whether  the  goiter  be  removed  or  not. 

The  recurrent  laryngeal  nerve,  which  has  been  described  with  the  pneumo- 
gastric  nerve,  should  now  be  observed  passing  upward  in  the  groove  between  the 
trachea  and  esophagus  and  behind  and  internal  to  the  lateral  lobe  of  the  thyroid 
gland  to  enter  the  larynx. 

The  Subclavian  Artery. — The  origin,  course,  and  relations  of  the  sub- 
clavian arteries  differ  uj)on  the  two  sides.  The  right  subclavian  is  a  branch  of  the 
innominate  artery,  and  the  left  of  the  arch  of  the  aorta.  The  anterior  scalene 
muscle  passes  in  front  of  the  subclavian  artery  and  divides  it  into  three  portions. 
The  first  portion  is  situated  between  its  origin  and  the  inner  border  of  the  anterior 
scalene  muscle,  the  second  portion  behind  the  muscle,  and  the  third  portion  between 
the  outer  border  of  the  muscle  and  the  lower  border  of  the  first  rib.  The  first  por- 
tion of  the  artery  is  the  one  which  differs  in  course  and  relations  on  the  two  sides ; 
it  will,  therefore,  be  described  separately. 

The  right  subclavian  artery  is  the  shorter  of  the  two.  It  arises  as  one  of 
the  two  terminal  divisions  of  the  innominate  artery  behind  the  upper  border  of  the 
right  sterno-clavicular  articulation.  The  first  portion  of  the  artery  lies  deep  in 
the  neck,  and  ascends  upward  and  outward  to  the  inner  border  of  the  anterior 
scalene  muscle.  It  is  covered  in  front  by  the  skin,  the  superficial  fascia,  the 
platysma  myoides  muscle,  the  superficial  layer  of  the  deep  fascia,  the  sternal  end  of 
the  clavicle,  the  sterno-mastoid  muscle,  the  anterior  jugular  vein,  the  sterno-hyoid 
and  sterno-thyroid  muscles,  and  the  posterior  process  of  the  deep  fascia  (prever- 
tebral fascia)  continued  forward  from  in  front  of  the  scaleni  muscles.  It  is  crossed 
by  the  internal  jugular  and  vertebral  veins,  the  pneumogastric  nerve,  the  superior 
cardiac  nerves  and  a  loop  of  the  .sympathetic  nerve  (ansa  "\''ieussenii),  and  the 
phrenic  nerve.     Below  the  artery  are  the  pleura,  the  recurrent  laryngeal  nerve, 


128  SURGICAL  ANATOMY. 

and  the  subclavian  vein  ;  behind  it  are  the  recurrent  laryngeal  nerve,  the  cord  of 
the  sympathetic  nerve  with  its  middle  and  inferior  cardiac  branches,  the  longus 
colli  muscle,  the  transverse  process  of  the  seventh  cervical  or  first  thoracic  vertebra, 
from  which  it  is  separated  by  a  small  quantity  of  cellular  tissue  and  fat,  and  the 
apex  of  the  lung,  covered  with  pleura. 

The  left  subclavian,  the  longer  of  the  two  arteries,  arises  from  the  transverse 
portion  of  the  arch  of  the  aorta  opposite  the  third  thoracic  verteljra.  Its  first 
portion  ascends  almost  vertically  to  the  inner  margin  of  the  first  ril)  and  the  inner 
border  of  the  insertion  of  the  anterior  scalene  muscle.  Only  the  relations  of  the 
cervical  part  of  this  portion  of  the  artery  will  be  described  here.  The  cervical  part 
of  the  first  portion  is  covered  by  the  skin,  the  superficial  fascia,  the  platysma 
myoides  muscle,  the  superficial  layer  of  tlie  deep  fascia,  the  sterno-mastoid  muscle, 
the  anterior  jugular  vein,  the  sternodiyoid  and  sterno-tliyroid  muscles,  the  po.sterior 
process  of  the  deep  fascia,  continued  forward  from  in  front  of  the  scaleni  nmscles, 
the  sternal  end  of  the  clavicle,  the  left  internal  jugular  vein,  the  vertebral  and  sub- 
clavian veins,  the  apex  of  the  left  king  and  its  pleura,  the  phrenic  nerve,  and  the 
cardiac  branches  of  the  sympathetic  nerve,  which  lie  parallel  with  the  artery,  the 
left  common  carotid  artery,  and  the  thoracic  duet.  On  its  outer  side  are  the  apex 
of  the  lung  and  pleura ;  on  its  iinier  side  are  the  trachea,  the  recurrent  laryngeal 
nerve,  the  esophagus,  and  the  thoracic  duct ;  behind  it  are  the  pleura  and  the 
apex  of  the  left  lung,  while  behind  and  internal  to  it  are  the  thoracic  duct,  the 
esophagus,  the  inferior  cervical  ganglion  of  the  symj^athetic  nerve,  the  sympathetic 
cord,  the  longus  colli  muscle,  and  the  spinal  column. 

Differences  Betweai  the  Right  and  Left  Subclavian  Arteries  in  Their  First  Por- 
tion.— The  first  portion  of  the  left  subclavian  artery  differs  from  the  first  portion  of 
the  right  in  the  following  respects :  The  left  subclavian  arises  directly  from  the 
arch  of  the  aorta,  while  the  right  arises  from  the  innominate  artery  ;  it  lies  deeper, 
is  longer  and  more  vertical ;  it  is  in  relation  with  the  esophagus  and  the  thoracic 
duct,  while  the  right  is  not ;  it  is  crossed  liy  the  left  innominate  or  brachio-ceplialic 
vein,  the  phrenic  and  ])neumogastric  nerves,  and  the  cardiac  branches  of  the  sym- 
pathetic nerve  running  almost  paralk4  with  it ;  on  the  right  side  the  phrenic  and 
pneumogastric  nerves  and  some  of  the  cardiac  branches  of  the  sympathetic  nerve 
pass  in  front  of  the  right  subclavian  artery,  at  nearly  a  right  angle.  The  left 
subclavian  artery  is  not  in  so  close  a  relation  with  the  recurrent  laryngeal  nerve  as 
is  the  right  subclavian,  the  nerve  winding  around  below  the  latter.  In  the  follow- 
ing description  of  the  cour.se  of  the  thoracic  duet  it  will  l)o  seen  to  be  in  relation 
with  llic  lir.st  portion  of  the  loft  s;d)clavian  artery  at  two  points;  it  holds,  of  course, 
no  relation  to  the  I'ight  subclavian  artery. 

The  thoracic  duct  passes  upward    and    out  of  the  chest   to  the  left  of  the 


PLATE  XXVI, 


Esophagus 
Trachea  (lower  portion  removed) 
Thyroid  body 


Scalenus  medius  m 

Scalenus 
posticus  m 


Thoracic  duct 

Vertebral  a. 

Common  carotid  a. 

Inferior  thyroid  a. 
Internal  jugular  v. 

Scalenus  anticus  m. 


Internal  mammary  a. 

Right  innominate  v 

Superior  vena  cava 

Innominate  a'. 


Aorta  (a) 


Transversalis  colli  a. 
Suprascapular  a. 
Subclavian  v. 
Internal  jugular  v. (cut) 
Subclavian  a. (1st  portion) 
Vertebral  v. 
Left  innominate  v. 


Left  bronchus 


ri— 9 


THORACIC  DUCT. 
129 


DISSECTION  OF  THE  NECK.  131 

eso[)hagus  and  beliiml  the  lirst  |)orti()ii  of  the  suhclavian  artery  ami  tlie  apex 
of  the  left  lung.  llehind  llie  left  internal  jugular  vein  and  eonnuon  carotid 
artery,  and  opposite  the  seventh  eervieal  vertebra,  the  duet  forms  an  arrli  aliove 
the  subclavian  artery  and  anterior  to  tiie  vertebral  arteiy  and  vein,  and  descends 
in  front  of  the  anterior  scalene  muscle  to  empty  into  tlie  left  subclavian  vein  at 
its  junction  with  the  internal  jugular  vein. 

The  Second  Portion  of  the  Subclanan  Artery. — The  relations  of  the  subclavian 
artery  in  its  second  and  tliinl  poi'tions  are  alike  on  its  two  sides.  In  its  second 
portion  the  artery  lies  behind  the  scalenus  anticus  and  in  front  of  the  scalenus 
medius  muscle  ;  at  this  point  it  rises  highest  above  the  clavicle,  usually  about  three- 
fourths  of  an  inch.  It  is  covered  by  the  skin,  the  superficial  fascia,  the  platysma 
myoides  muscle,  the  superficial  layer  of  the  deejj  fascia,  the  clavicular  origin  of 
the  sterno-mastoid  muscle,  the  jaosterior  process  of  the  deep  fascia,  the  phrenic 
nerve,  and  the  anterior  scalene  muscle,  the  latter  separating  it  from  the  subclavian 
vein.  Above  it  lies  the  lower  of  the  three  cervical  trunks  of  the  axillarj'  or 
brachial  plexus  of  nerves.  Behind  it  are  the  middle  scalene  muscle  and  the  apex 
of  the  lung  and  pleura.  Below  it  lies  the  pleura,  while  below  and  in  front  of  it 
is  the  subclavian  vein.  This  portion  gives  off  but  one  branch,  the  superior  inter- 
costal artery. 

Tlie  Third  Portion  of  the  Subclavian  Artery. — In  the  third  part  of  its  course  the 
artery  passes  downward  and  outward  from  the  external  margin  of  the  anterior 
scalene  muscle  to  the  lower  border  of  the  first  rib,  occupying  the  subclavian  tri- 
angle, where  it  is  nearer  the  surftice  than  in  either  the  first  or  second  portion  of 
its  course.  It  is  covered  by  the  skin,  the  superficial  fascia,  the  platysma  myoides 
muscle,  the  superficial  layer  and  the  posterior  of  the  two  processes  of  the  deep 
fascia,  and  near  its  termination  by  the  clavicle  and  subclavius  muscle.  Running 
in  front  of  this  portion  are  the  supra-scapular  artery  and  vein,  while  crossing  it 
are  the  clavicular  branches  of  the  cervical  plexus,  the  nerve  to  the  subclavius 
muscle,  and  the  external  jugular  vein.  The  tran.sversalis  colli,  supra-scapular,  pos- 
terior jugular,  and  jugulo-cephalic  veins,  which  frequently  form  a  plexus  in  front 
of  the  artery,  and  should  be  borne  in  inind  in  ligating  the  third  portion  of  the  sub- 
clavian artery,  empty  into  the  external  jugular  vein.  The  relation  between  the 
supra-scapular  artery  and  the  third  portion  of  the  subclavian  artery  at  its  point  of 
election  can  be  compared,  surgically,  to  the  relation  held  between  the  middle 
sterno-mastoid  and  the  connnon  carotid  artery  at  its  point  of  election.  The  ana- 
tomic difference  is,  however,  that  the  middle  sterno-mastoid  arterj^  passes  across  the 
sheath  of  the  common  carotid,  and  is  frequently  severed  in  the  ligation  of  the  latter, 
wjiile  the  su]>ra-seapular  passes  in  front  of,  and  almost  parallel  with,  the  subclavian 
artery,  and  can  be  displaced  when  the  main  vessel  is  ligatured.     The  subclavian 


132  SURGICAL  AXATOMY. 

vein  lies  below  the  artery,  and  on  a  jilane  anterior  to  it.  Above  and  to  the  outer 
side  of  this  portion  of  the  artery  are  the  tliree  ecrvical  trunks  of  the  axillary  or 
brachial  plexus  of  nerves  and  the  omo-hyoid  muscle.  The  upper  trunk  runs  so 
close  to  and  so  nearly  parallel  with  the  arter}'  that  it  may  be  mistaken  for  it  and 
tied,  the  surgeon  being  misled  by  the  pulsation  communicated  to  the  nerve. 
Behind  the  artery  are  the  middle  scalene  muscle  and  the  lower  cervical  trunk  of 
the  brachial  plexus.  Below  this  portion  of  the  artery  is  the  first  rib.  The  third 
portion  of  the  subclavian  artery,  as  a  rule,  gives  off  no  branches,  but  occasionally 
gives  origin  to  the  posterior  scapular  artery. 

Variations  of  the  subclavian  artery. — Tlie  right  subclavian  artery  may  arise 
as  a  separate  trunk  from  the  arch  of  the  aorta.  It  may  pass  in  front  of  or  through 
the  fibers  of  the  anterior  scalene  muscle,  and  ascend  as  high  as  one  and  one-half 
inches  above  the  clavicle.  In  some  cases  the  subclavian  vein  passes  with  the  artery 
behind  the  anterior  scalene  muscle. 

Ligation  of  the  third  portion  of  the  subclavian  artery. — The  third  portion 
is  the  jjoint  of  election  for  ligation  of  the  subclavian  artery  ;  in  this  portion  it  is 
most  superficial,  is  covered  by  fewer  important  structures,  and,  as  a  rule,  gives  off 
no  branches ;  the  posterior  scapular  artery  occasionally  arises  from  it.  When 
performing  this  ligation  the  patient  should  Ije  placed  in  the  supine  position,  with  a 
pillow  beneath  the  upper  part  of  the  back,  and  the  shoulder  depressed.  The  in- 
cision is  made  parallel  with  the  upper  border  of  the  clavicle,  should  be  three  or 
four  inches  in  length,  and  commence  at  the  outer  border  of  the  clavicular  origin 
of  the  sterno-mastoid  muscle.  The  vessel  is  brought  nearer  the  surface  by  carrj'- 
ing  the  arm  to  the  side  and  depressing  the  shoulder,  thus  diminishing  the  depth 
of  the  triangle  through  which  the  artery  passes.  The  relation  of  the  supra-scapu- 
lar vessels  to  the  third  portion  of  the  subclavian  artery  is  so  changed  when  the 
arm  is  well  drawn  down  that  it  is  not  endangered  in  the  ligation.  The  following 
structures  are  divided  :  the  skin,  the  superficial  fascia,  the  platysma  myoides 
muscle,  some  of  the  clavicular  branches  of  the  cervical  plexus  of  nei'\'es,  the  super- 
ficial layer  of  the  deep  fascia,  and  the  posterior  of  its  two  processes  (prevertebral 
fascia).  The  external  jugular  vein,  with  tlio  veins  emptying  into  it,  which  frequently 
form  a  plexus  above  and  in  front  of  the  subclavian  artery  Viet  ween  the  two  layers 
of  the  deep  fascia  (superficial  and  prevertebral),  should  be  pushed  aside  ;  if  this  is 
not  feasible,  they  may  be  tied  and  severed  between  ligatures.  The  posterior  belly 
of  the  omo-hyoid  muscle  should  next  be  exposed  by  dividing  the  connective  tissue 
at  the  bottom  of  the  wound  ;  tlie  operator  then  searches  for  the  upper  cervical 
trunk  lA'  the  axillary  or  brachial  plexus  of  nerves  and  the  outer  border  of  the 
anterior  scalene  muscle,  along  wliich  the  finger  is  jtassed  until  the  tuliercle  on  the 
first  rib  is  reached,  provi<K'd  the  vessel  is  not  felt,  pulsating  before  the  finger  I'eaches 


PLATE  XXVII. 


Circle  of  Willis 
Superficial  temporal  a 


Internal  maxillary  a. 
Occipital  a 
External  carotid  a 
Princeps  cervicis  a 
Internal  carotid  a. 
Ligature  on  common  carotid  a 

Ascending  cervical  a 


terior  circumflex  a 


Facial  a. 


Lingual  a. 


Superior  thyroid  a. 

Vertebral  a 
Common  carotid  a. 


—Subclavian  a. 

Jhyroidea  ima  (a.) 
Innominate    a 

Superior  thoracic  a. 
Yas  aberrans  (a.) 

Intercostal  arteries 
Aorta  (a.) 

Long  thoracic  a. 


Dorsalis  scapulae  a. 
Subscapular  a. 

Internal  mammary  a. 
Posterior  circumflex  a. 


COLLATERAL  CIRCULATION  AFTER  LIGATION  OF  SUBCLAVIAN  AND  COMMON  CAROTID  ARTERIES. 


133 


DJS1SECTW^'  OF  TllE  M-X'K.  IJi.') 

the  rib.  Tf  the  imlsations  of  tlic  artery  he  felt,  its  sheath  siioukl  be  opened  ami 
tiie  aneurysm  iieeillc,  earryint;-  the  ligature,  passed  from  before  backward,  away 
from  the  vein,  and  tiieii  frnm  btdow  npward,  eare  beinp;  taken  to  avoid  ineludini!; 
tlie  lowest  I  if  the  three  eervieal  trunks  (if  tlie  axillary  or  liraeliial  plexus,  wliieh  runs 
behind  and  nearly  jiaralKd  with  tlu'  third  piirlidu  nf  the  suiiela\'i;iii  ai'teiA'.  In 
very  muscular  subjects,  in  addition  to  the  above  structures,  it  may  1k'  necessary  to 
divide  a  jiortion  of  the  c'lavieular  head  of  the  sterno-mastoid  and  tlie  anterior 
border  of  the  trapezius  muscle. 

After  this  ligation  the  collateral  cirndation  is  carried  <in  by  the  anastomosis 
of  the  supra-sca])ulai'  and  posterior  sca]iular  arteries  with  the  dorsalis  sca|iuke  and 
the  terminal  |iortion  of  the  subscapular  artery,  the  snijra-scapular  above,  with  the 
acromio-thoracic  and  posterior  circuniHex  arteries  l)elow,  and  by  the  anastomosis 
of  the  .superior  thoracic,  thoracic  branches  of  tlie  acromio-thoracic,  the  long 
thoracic,  and  the  subscapular  arterj-,  witli  the  aortic  intercostal  arteries,  the  internal 
mammary,  and  the  superior  intercostal  artery. 

Ligation  of  the  second  portion  of  the  subclavian  artery  is  very  rarely 
performed.  The  vessel  is  exposed  by  an  incision  along  the  clavicle,  as  in  tlie 
foregoing  ligation;  in  addition,  the  clavicular  head  of  the  sterno-mastoid  muscle 
is  divided,  the  connective  tissue  is  cleared  away,  and  any  veins  which  may  be 
found  overlying  the  prevertebral  fascia  covering  the  anterior  scalene  muscle  are 
tied.  The  prevertel)ral  fascia  is  divideil,  the  phrenic  nerve  carried  inward,  and 
the  anterior  scalene  muscle  severed  near  its  attaclnnent  to  the  first  rib,  care  being 
taken  not  to  injure  the  anterior  jugidar,  external  jugular,  internal  jugular,  and 
.subclavian  veins  or  the  pleura.  The  needle  should  be  carried  from  beibre  back- 
ward and  below  npward  to  avoid  injuring  the  vein,  as  in  ligating  the  third  portion 
of  the  artery. 

Ligation  of  the  first  portion  of  the  subclavian  artery  is  the  most  ditlieult 
of  the  three  ligations,  especially  of  the  left  .su1)clavian  artery.  This  portion  of  the 
ves.sel  lies  deeper  than  the  other  two  ]iortions,  is  si;rrounded  more  intimately  by 
important  structures,  and  gives  off  three  branches.  (See  description  of  tln' 
relations  of  the  first  portion.)  To  expose  this  portion  of  the  vessel  on  the  right 
side  make  a  triangular  flap,  like  that  made  in  tying  the  innominate  artery, 
by  carrying  an  incision  along  the  inner  liorder  of  the  steriio-mastoi<l  nuiscle  and 
one  along  the  upper  border  of  the  clavicle.  The  skin,  superficial  fascia,  jilatysma 
myoides  muscle,  superficial  layer  of  the  deep  fascia,  and  the  anterior  jugular  vein 
are  divided.  The  sternal  head  of  the  sterno-mastoid  muscle,  and,  if  necessary,  the 
clavicular  head,  as  well  as  the  sterno-hyoid  and  sterno-thyroid  nuiscles  at  their 
origin,  are  divided.  The  inferior  thyroid  veins,  now  seen  at  the  bottom  of  the 
wound,  should  be  lield  aside  or  divided  between  ligatures,  and  the  root  of  the  com- 


136  SURGICAL   AXATOMV. 

mon  carotid  artery  exposed  ;  this  artery  is  tlien  followed  downward  to  the  innomin- 
ate, thus  reaching  the  first  part  of  the  subclavian  artery.  To  expose  the  first 
portion  of  the  left  subclavian  artery  a  flap  similar  to  that  described  in  exposing 
the  same  jiortion  of  tlie  right  should  be  made.  The  sterno-mastoid,  the  sterno- 
hyoid, and  the  sterno-thyroid  muscle  are  divided,  and  the  apex  of  the  left  lung, 
with  the  structures  running  parallel  to  and  in  front  of  the  artery  (see  description 
of  the  relations  of  the  first  portion  of  the  left  subclavian  artery),  should  be  dra\\n 
forward,  the  vertebral  and  internal  jugular  veins  avoided,  and  the  aneurysm 
needle  passed  from  below  ujn\'ard.  In  carrying  the  needle  behind  the  artery, 
unless  great  care  be  exercised,  the  thoracic  duct  and  pleura  may  be  wounded. 

Branches  of  the  SuBCL.iviAN  Artery. — These  consist  of  the  vertebral,  the 
thyroid  axis,  the  internal  mammary,  and  the  superior  intercostal  artery.  The 
first  three  branches  arise  from  the  first  portion  of  the  arterj^ ;  the  fourth  branch 
arises  from  the  second  portion.  In  the  majority  of  ca.ses  the  third  portion  gives  off 
no  branches,  but  the  posterior  scapular  artery  frequently  arises  from  it. 

Tlie  vertebral  artery,  the  first  and  largest  branch,  arises  from  the  upper  and 
back  part  of  the  first  portion  of  the  subclavian  artery.  It  ascends  in  the  interval 
between  the  scalenus  anticus  and  longus  colli  muscles,  entering  the  foramen  in  the 
transverse  process  of  the  sixth  cervical  vertebra,  just  below  the  level  of  the  lower 
border  of  the  cricoid  cartilage.  It  continues  upward  through  the  foramina  in  the 
transverse  processes  of  the  remaining  cervical  vertebrae  to  the  skull.  Having 
passed  through  the  foramen  in  the  transverse  process  of  the  axis,  it  makes  an 
S-shaped  curve  upward  and  outward,  which  prevents  its  being  strefcheil  when  the 
head  is  rotated.  It  then  passes  through  the  foramen  in  the  transverse  process  of 
the  atlas,  curving  backward  behind  the  articular  process  in  a  deep  groove  on  the 
upper  surface  of  the  posterior  arch  of  the  atlas.  Here  it  lies  in  the  suboccipital 
triangle,  and  pierces  the  posterior  occipito-atloid  ligament  and  dura  mater  of 
the  spinal  cord  to  traverse  the  foramen  magnum  ami  become  intra-cranial.  It 
unites  with  the  vertebral  artery  of  the  opposite  side  near  the  lower  border  of  the 
pons  Varolii  to  form  the  basilar  artery.  The  first  or  cervical  portion  of  the  verte- 
bral arterj'  lies  behind  the  internal  jugular  vein,  the  inferior  thyroid  artery,  and 
the  vertebral  vein,  while  near  tlie  tran.sverse  process  of  the  sixth  cervical  verte- 
bra it  lies  between  the  scalenus  anticus  and  longus  colli  muscles ;  the  thoracic 
duct  lies  in  front  of  the  left  vertebral  artery.  The  second  or  vertebral  portion  lies 
witliin  tiie  canal  formed  liy  the  foramina  of  the  transverse  processes  of  the  upper 
six  cervical  vertebrre,  and  is  accompanied  by  the  vertebral  veins  and  the  vertebral 
])lexus  of  nerves  derived  from  the  inferior  cervical  sympathetic  ganglion  ;  it  lies 
between  the  vertebral  \iiii  in  front,  and  the  cervical  nerves,  which  pass  out  of  the 
spinal  canal  through  the  intervertebral  foramina,  beliind.     It  is  in  contact  with  the 


PIATF.  XXIX. 


External  carotid 
Internal  maxillary  v 
Temporal  v 
Posterior  auricular  a 
Posterior  auricular  v. 


Complexus  m. 


Levator  anguli  scapulae  m 

Transversalis  colli  v, 

Serratus  magnus 

Posterior  belly  of  omo-hy 

Scalenus  medius  m 


Suprascapular  a. 
Suprascapular  v. 

Subclavian  a. (3d  portion) 
Transversalis  colli  a. 


Sterno-thyroid  m« 


VESSELS  OF  NECK, 
140 


PLATF.  XXX. 


Facial  n 
Posterior  auricular  n.and  v 


Nerve  to  stylo-hyoid  m.and  posterior  belly  of  digastric  m. 
Hypoglossal  n. 

Descendens  hypoglossi  n. 
Lingual  V. 

Submaxillary  gland 
Mylo-hyoid  n. 


Superficial  cervical  n 
Posterior  thoracic  n 
Suprascapula 


Brachial  plexus 


MUSCLES  AND  NERVES  OF  NECK. 
141 


I 


DISSECTTOy  OF  Till-:  .XKck'.  ]4;] 

intorti'ansvcrse  muscles.  Its  tliird  or  (jccipitdl  jitniiun  lies  in  the  fiTonve  on  tiie 
jtosterior  areh  ot'tlie  atlas,  where  it  rests  ujiun  tlie  suboccipihil  ncrvt',  aiul  is  within 
the  suboccipital  trian,i;le  tonne ■(!  hy  tlic  reetus  eapitis  posticus  major  nnisclc  upon 
the  inner  side,  the  ohlicpuis  capitis  superior  above  and  the  <ilili(|uus  capitis  iid'crior 
nuisele  below ;  it  is  covered  by  the  eomplexus  muscle.  The  relation  Avhieh  the 
fourth  or  intm-cranial  portion  holds  within  the  cranial  cavity  is  described  under 
the  Dissection  of  the  Brain. 

The  Branches  of  the  A'kutebkal  Artery. — These  consi.st  of  two  sets: 
those  given  off  in  the  neck  and  those  given  off  witjiin  tlic  cranial  cavity.  The 
branches  given  off  in  the  neck  are  the  lateral  spinal  and  the  inustailar. 

The  lateral  spinal  arteries  pass  through  tlie  intervertebral  foramina,  and 
each  divides  into  two  branches  for  the  supply  of  the  sjiinal  cord,  its  membranes, 
and  the  bodies  of  the  vertebrae. 

The  muscular  branches  are  given  off  immediately  l)efore  the  vertebral  arteiy 
pierces  the  occipito-atloid  ligament ;  they  sujjply  the  deep  muscles  of  the  neck,  and 
anastomose  with  the  ascending  cervical,  occipital,  and  deep  cervical  arteries. 

The  vertebral  vein  is  formed  in  the  suboccipital  triangle  from  a  plexus  of  veins 
composed  of  numerous  small  branches  from  the  deep  muscles.  It  enters  the  fora- 
men in  the  transverse  process  of  the  atlas,  and  forms  a  plexus  around  the  verte- 
bral artery.  At  the  lower  part  of  the  neck  the  jilexus  unites  to  form  the  vertebral 
vein,  which  emerges  at  the  foramen  in  the  transverse  process  of  the  sixth  cervical 
vertebra,  whence  it  passes  downward  in  front  of  the  vertebral  artery  and  behind 
the  internal  jugular  vein  and  terminates  in  the  innominate  vein  near  its  origin, 
passing  in  front  of  the  first  portion  of  the  subclavian  arte^y^  Its  orifice  is 
guarded  by  a  pair  of  valves.  It  receives  as  tributaries  the  veins  from  the  neigh- 
boring muscles  ;  the  dorsi  spinalis  veins,  the  veins  from  the  spinal  canal  (the 
meningo-rachidian  veins),  the  deep  cervical,  and,  at  times,  the  first  pair  of  inter- 
costal veins.  In  cases  where  the  jiosterior  condyloid  foramen  is  present,  the  verte- 
bral vein  communicates  with  the  lateral  sinus  by  a  branch  which  passes  through 
the  foramen. 

Ligation  of  the  vertebral  artery  is  performed  through  an  inc'ision  carriecl 
along  the  lower  part  of  the  posterior  border  of  the  sterno-niastoid  muscle,  whicli 
corresponds  to  the  outer  border  of  the  anterior  scalene  nniscle.  The  .skin,  super- 
ficial fascia,  platysma  myoides  muscle,  and  the  superficial  layer  of  the  deep  fascia 
are  divided,  the  external  jugular  vein  being  displaced  outward.  The  sterno- 
mastoid  muscle  is  drawn  toward  the  median  line,  and  the  connective  tissue 
divided  or  pushed  aside  with  the  handle  of  the  scalpel,  thus  exposing  the  pre- 
vertebral fascia  or  jiosterior  process  of  the  deep  cervical  fascia  whicli  covers  the 
anterior  scalene  muscle  and  the  j)hrenie  nerve.     The  posterior  process  of  the  deep 


144  SURGICAL   ANATOMY. 

cervical  fascia  (preverteliral  iascia)  is  divided  on  a  line  with  the  inner  horder  of 
the  anterior  scalene  muscle  ;  the  vertebral  artery  with  its  companion  vein,  which 
parti}-  covers  it,  will  be  found  occu})ying  the  interval  between  the  anterior  scalene 
and  the  longus  colli  muscle.  The  inferior  tliyroid  arterj-,  which  lies  in  front  of  the 
vertebral  artery,  must  not  be  mistaken  for  it.  The  dissection  necessary  to  expose 
the  vessel  must  be  done  cautiously,  otherwise  there  is  danger  of  wounding  the 
phrenic  nerve  and  the  internal  jugular  vein,  or  of  opening  the  pleural  sac.  The 
inexperienced  operator  may  be  led  to  believe  he  has  opened  the  pleural  sac,  by  the 
crackling  sound  occasioned  by  air  infiltrating  the  connective  tissue  occupying  this 
position.  The  vertebral  vein  must  be  slightly  displaced  before  passing  the  aneu- 
rysm needle,  Avhich  should  be  carried  from  without  inward  to  avoid  injuring  the 
vertebral  vein,  the  internal  jugular  vein  being  protected  with  the  tip  of  the  finger. 
On  the  left  side  the  thoracic  duct  should  be  avoided.  Contraction  of  the  pupil  of 
the  ej'e  of  the  corresponding  side,  caused  by  the  disturbance  of  the  sympathetic 
filaments  in  relation  with  the  artery,  is  evidence  that  tlie  ligature  has  included  the 
vertebral  artery.  The  author  has  found  this  a  reliable  sign.  The  carotid  tubercle, 
which  is  at  the  upper  extremity  of  the  groove  bet-sveen  the  scalenus  anticus  and 
longus  colli  muscles,  is  the  deep  guide  to  the  artery. 

The  thyroid  axis,  a  short  thick  trunk,  arises  i'mm  the  sulxdavian  artery  near 
the  inner  liorder  of  the  anterior  scalene  muscle.  It  lies  beneatli  the  internal 
jugular  vein  and  ju'evertebral  fascia  and  between  tlic  i)hrenic  nerve  and  vertebral 
vein,  and  divides  into  three  Branches  :  tlie  inferior  thyroid,  supra-scapular,  and 
tran.sversalis  colli  arteries. 

The  inferior  thyroid  artery,  the  largest  brancli  of  tlie  thyroid  axis,  passes 
obliquely  upward  and  inward  behind  the  internal  jugular  vein,  and  in  front  of 
the  vertebral  artery  and  inward  bcliind  the  sheath  of  the  common  carotid  artery 
and  the  sympathetic  nerve  to  the  deep  .surftice  of  the  lateral  lobe  of  the  tliyroid 
gland,  which  gland  it  supplies  and  within  which  it  anastomoses  with  the  superior 
tliyroid  artery  and  the  inferior  thyroid  artery  of  the  opposite  side.  It  turns 
inward  just  below  the  carotid  tubercle  (anterior  tubercle  of  the  sixth  cei'vical 
transverse  process),  and  crosses  brhind  the  sheath  of  the  ves.sels  at  al)out  the 
level  of  the  tenddii  of  tlie  oiiKi-hyoid  muscle.  Tlie  middle  cervical  or  thyroid 
ganglion  of  the  sympathetic  nerve  rests  U}iiiii  tbe  inferior  thyroid  artery.  It  gives 
off  the  following  Uranciies  :  ascending  cervii-al,  laryngeal,  tracheal,  esophageal, 
and  muscular. 

The  ascendinr/  cervical  artery  arises  from  the  inferior  tliyroid  !>eliinil  the 
intei-iial  jugular  x'eiii,  and  runs  up  the  neck  close  to  tlie  ti|is  of  the  transverse 
processes  of  the  cervical  vertebra;  in  the  groove  between  the  anterior  scalene  and 
the  rectus  capitis  anticus  major  muscle,  and  to  tin'  inner  side  of  the  phrenic  nerve. 


DISSECTION  OF  THE  NECK.  1  i:, 

Its  braiH'hos  to  tlic  nmsclrs  of  tlic  neck  coniimmiciitc  w  ilh  tin-  muscular  liranclics 
of  the  verteliral  artery,  wliile  ntlK'r;*  enter  tlie  intcrverteliral  riFraniiiia,  to  n'acli 
tiio  bodies  of  tlie  vertebra-  ami  the  spinal  cord  and  its  menini;es.  It  anastomoses 
with  tlie  verctehral,  ascending  i)haryngeal,  and  branches  of  the  occiiiital  artery. 
It  sends  a  branch  to  the  phrenic  nerve. 

The  iiifcriiir  luri/iif/cal  artcri/  accompanies  the  retairrent  laryngeal  nerve,  sup- 
plies the  nniscles  and  uuu-ous  inembrane  of  the  lai'ynx,  and  anastoiiuises  with  the 
superior  laryngeal  artery. 

The  fnifliral  bi-diichcs  ramity  upon  the  trachea,  the  lower  ones  anastomosing 
with  the  bronchial  arteries. 

The  esophageal  hnuiches  sujiply  the  esophagus.  One  of  these  is  often  large, 
runs  parallel  with  the  continuation  of  tlie  inferior  thyroid  artery,  and  may  be  mis- 
taken for  it. 

The  iHuacular  bra)iclies  supply  tlie  muscles  of  the  lower  anterior  part  of  the 
neck. 

The  infericir  thyroid  artery  is  not  accompanied  by  the  corresponding  vein, 
which  lies  at  the  side  of  tlie  median  line  of  tlie  neck.  (See  Dissection  of  Front  of 
Neck.) 

Ligation  of  the  inferior  thyroid  artery. — This  is  performed  either  where  the 
artery  lies  between  the  internal  jugular  vein  and  the  inner  border  of  the  anterior 
scalene  mu.scle,  or  to  the  inner  side  of  the  carotid  sheath  as  it  passes  to  the  deep 
surface  of  the  lateral  lobe  of  the  thyroid  gland  just  below  the  level  of  the  cricoid 
cartilage.  To  secure  the  inferior  thyroid  artery  along  the  inner  border  of  the 
anterior  scalene  muscle  make  an  incision  similar  to  that  made  in  ligation  of  the 
vertebral  artery,  carrying  the  aneurysm  needle  from  within  outward  away  from 
the  vertebral  vein.  To  secure  the  inferior  thyroid  artery  on  the  inner  side  of  tlie 
carotid  sheath  make  an  incision  along  the  anterior  border  of  the  sterno-mastoid 
muscle.  • 

Tlie  supra-scapular  artery  (transversalis  humeri),  smaller  than  the  transver- 
salis  colli  artery,  coarses  outward  across  the  lower  part  of  the  neck.  It  first  passes 
beneath  the  sterno-mastoid  muscle  and  over  the  phrenic  nerve  and  lower  part  of 
the  anterior  scalene  muscle;  then  it  runs  behind  the  clavicle  and  subclavius 
muscle,  crosses  the  third  part  of  the  subclavian  artery,  and  pa,sses  beneath  the 
posterior  belly  of  the  omo-hyoid  and  the  anterior  border  of  the  trapezius  muscle, 
to  the  superior  liorder  of  the  scapula,  where  it  passes  over  the  transverse  ligament 
of  that  lioiie  to  reacli  the  supra-spiiious  fossa.  The  .supra-scapular  nerve,  which 
joins  the  artery  just  before  it  dips  under  the  onio-h\-oid  muscle,  passes  beneath  the 
transverse  ligament,  and  through  the  supra-scapular  notch.  In  the  supra-spinous 
fo.ssa  the  artery  lies  close  to  the  bone,  and  supplies  the  supra-spinatus  muscle ;  at 

S—    11-10 


146  SURGICAL  ANATOMY. 

the  neck  of  the  scapula  it  turns  around  the  base  of  the  spine  to  the  infra-spinous 
fossa,  where  it  anastomoses  with  the  dorsahs  scapulae,  a  branch  of  the  subscapular 
artery,  and  with  the  posterior  scapular  artery.  The  chief  Branches  of  the  sujira- 
scapular  artery  are  the  inferior  sterno-mastoid,  supra-acromial,  and  articular. 
Other  branches  supjjly  the  subclavius  muscle,  the  skin  over  the  manubrium 
sterni  (suiara-sternal),  and  the  clavicle. 

The  inferior  sterno-mastoid  artery  supplies  the  clavicular  jiortion  of  the  sterno- 
mastoid  muscle,  behind  which  it  is  given  off. 

The  supra-acromial  branch  pierces  the  trapezius  muscle,  passes  over  the 
acromion  process,  and  anastomoses  with  the  acromio-thoracic  and  posterior  circum- 
flex arteries. 

The  articular  branches  sujaply  the  acromio-clavicular  joint  and  the  shoulder- 
joint. 

The  transversalis  colli  artery,  or  transverse  cervical,  usually  larger  than  the 
supra-scapular  artery,  passes  outward  across  the  side  of  the  neck,  higher  than  the 
supra-scapular,  over  the  scalene  muscles  and  phrenic  nerve,  and  over  or  between 
the  cervical  trunks  of  the  axillary  or  brachial  plexus  to  the  anterior  border  of  the 
trapezius,  beneath  which,  and  at  the  outer  border  of  the  levator  anguli  scapulae 
muscle,  it  divides  into  its  two  terminal  Ijranches,  the  superficial  cervical  and  the 
posterior  scapular. 

The  superficial  cervical  artery  passes  upward  beneath  the  anterior  border  of  the 
trapezius  and  over  the  levator  anguli  scapula;  and  splenius  muscles.  It  supplies 
these  muscles  and  the  posterior  chain  of  lymphatic  glands  in  the  neck,  and  anas- 
tomoses with  the  suj^erficial  branch  of  the  arteria  princepS  cervicis,  which  descends 
from  the  occipital  artery  between  the  .splenius  and  complexus  muscles. 

The  posterior  scapular  artery,  the  larger  of  the  two  terminal  branches,  passes 
beneath  the  trapezius  and  the  levator  anguli  scapulas  muscle  to  the  superior  angle 
of  the  scapula,  whence  it  descends  along  the  vertebral  border  or  base  of  the 
scapula  to  the  inferior  angle.  It  runs  between  the  insertions  of  the  serratus 
magnus  muscle  in  front  and  the  rhomboidri  and  levator  anguli  scapuUe  muscles 
bi'liind,  which,  with  the  latissimus  dorsi  and  trapezius,  it  supplies.  It  anastomoses 
\\itli  the  supra-scapular  and  subscapular  arterit's,  and  with  the  posterior  branches 
of  the  intercostal  arteries.  It  frequently  arises  from  the  third  portion  of  the  sub- 
clavian artery,  and  in  sv;ch  cases  the  superficial  cervical  artery  usually  arises 
from  the  thyroid  axis. 

Tlie  veins  corresponding  to  the  Itranelies  of  tlie  thyroid  axis  empty  into  the 
external  jugular  vein,  exci'iit  the  inferior  tliyroid  vein,  which  goes  to  the  innomi- 
nate vein. 

The  Internal  Mammary  Artery  arisis  from   the  lower  margin  of  the  first 


DISSECTION  OF  THE  NECK.  147 

part  of  the  subclavian  arteiy  opposite  tlie  thyroid  axis.  It  passes  downward 
beneatli  the  elavicle,  tlie  suliclavius  nuiscle,  and  the  subclavian  vein,  and  enters 
the  eliest  between  tlie  cartilage  of  the  first  rib  and  the  pleura.  At  its  origin  it  is 
cro.ssed  from  without  inward  by  the  jihrenic  nerve.  Its  further  course  is  descril)ed 
under  the  Dissection  of  the  Thorax.  The  accompanying  veins  of  the  internal 
mannnary  artery,  two  in  number,  unite  to  form  a  common  trunk  which  empties 
into  tlie  innominate  vein. 

Tiie  Superior  Intercostal  Artery  arises  from  the  upper  margin  of  the  second 
portion  of  the  subclavian  artery,  and  occasionally  arises  from  the  first  portion 
upon  the  left  side.  It  arches  backward  and  a  little  upward  over  the  pleura,  and 
then  descends  behind  it,  giving  off  the  profunda  cervicis  artery  ;  it  tlien  passes  in 
front  of  the  neck  of  the  first,  and  sometimes  of  the  second,  rib,  giving  off  the  arte- 
ries of  the  first,  and  at  times  of  the  second,  intercostal  space,  and  a  ]>o.sterior 
branch,  which  is  distributed  to  the  muscles  of  the  back  and  to  the  spinal  cord  and 
its  membranes.  In  front  of  the  neck  of  the  first  rib  it  lies  between  the  first  thoracic 
sympathetic  ganglion  on  the  inner  side,  and  the  anterior  branch  of  the  first  thor- 
acic nerve  on  the  outer  side.  Its  Branches  are  the  deep  cervical,  the  first  inter- 
costal, and  the  arteria  aberrans. 

The  deep  cervical  artery  (profunda  cervicis)  passes  backward  between  the 
seventh  and  eighth  cervical  nerves,  and  then  between  the  transverse  process  of  the 
last  cervical  vertebra  and  the  neck  of  the  first  rib,  internal  to  the  middle  and  pos- 
terior scalene  muscles  ;  thence  it  passes  up  the  back  of  the  neck  between  the  com- 
plexus  and  .semi-spinalis  colli  muscles,  which  it  supplies,  and  anastomoses  with 
the  arteria  princeps  cervicis  and  branches  of  the  ascending  cervical  and  vertebral 
arteries. 

The  deep  cervical  vein  liegins  in  the  suboccipital  triangle,  usually  receives  the 
occipital  vein,  accomj^anies  the  arteria  princeps  cervicis,  and  then  the  profunda 
cervicis  artery,  and  em])ties  into  the  vertebral  or  innominate  vein. 

The  first  intercostal  artery  has  a  distribution  in  the  first  intercostal  space 
corresponding  with  that  of  the  arteries  in  the  other  intercostal  spaces. 

The  arteria  aberrans,  inconstant,  arises  from  the  inner  side  of  the  right 
superior  intercostal  artery,  and  passes  downward  behind  the  esophagus,  supplying 
adjacent  structures  and  sometimes  joining  a  small  ascending  branch  of  the  aorta. 
oi)posite  the  third  thoracic  vertebra. 

The  anastomosis  between  the  superior  intercostal  and  the  occipital  artery 
performs  an  important  part  in  the  development  of  the  collateral  circulation  after 
ligation  of  the  common  carotid  artery. 

The  veins  wliieh  correspond  to  the  superior  intercostal  arteries  are  the  right 


148  SURGICAL  ANATOMY. 

and  left  superior  intercostal  veins.  The  left  superior  intercostal  vein  empties  into 
the  left  innominate  vein,  and  the  right  into  the  vena  azygos  major  or  the  right 
innominate  vein. 


The  Axillary  or  Brachial  Plexus. — Tlie  axillary  or  brachial  plexus  of  nerves 
will  be  seen  at  the  side  of  the  neck,  emerging  from  between  the  anterior  and 
middle  scalene  muscles  ;  it  is  formed  by  tlie  union  of  the  anterior  branches  of 
the  lower  four  cervical  nerves  and  by  the  greater  j^ortion  of  the  anterior  branch 
of  the  first  thoracic  nerve.  A  small  branch  from  the  anterior  division  of  the  fourth 
cervical  and  another  from  the  second  thoracic  nerve  usually  enter  the  plexus. 
These  branches  form  tlie  cords  of  the  plexus,  from  wlucli  are  given  off  the 
branches  that  supply  the  upper  extremity.  The  nerves  in  the  neck  are  arranged 
as  follows :  the  anterior  branches  of  the  fifth  and  sixth  cervical  nerves  unite 
bej'ond  the  outer  border  of  the  anterior  scalene  muscle  to  form  an  upper  trunk  ; 
the  anterior  branch  of  the  seventh  cervical  nerve  remains  distinct  as  the  middle 
trunk  ;  the  anterior  branches  of  the  eighth  cervical  and  first  thoracic  nerves  unite 
between  the  scalenus  anticus  and  scalenus  medius  muscles  to  form  the  lower 
trunk.  The  upper  and  middle  trunks  run  above  and  parallel  with  the  subclavian 
artery,  but  on  a  posterior  plane,  while  tlie  lower  trunk  passes  behind  the  artery. 
The  three  trunks  accompany  the  artery  between  the  clavicle  and  first  rib  on 
their  way  to  the  axilla.  These  three  trunks  separate  into  anterior  and  poste- 
rior divisions,  the  anterior  divisions  of  the  upper  and  middle  trunks  forming  the 
outer  cord,  that  of  the  lower  trunk  continuing  as  the  inner  cord,  and  all  the 
posterior  divisions  uniting  to  form  the  posterior  cord.  (For  a  desci'iption  of  the 
plexus  within  the  axilla  see  Dissection  of  Axilla.) 

The  branches  of  the  axillary  or  brachial  plexus  are  divided  into  two  sets : 
tliose  given  off  above  the  clavicle  and  those  arising  below  tliat  bone.  The 
branches  arising  above  the  clavicle  are  the  nerves  to  the  subclavius,  rhomboidei, 
scaleni,  and  longus  colli  muscles,  the  posterior  or  long  tlioraeic  nerve  (the  external 
respiratory  nerve  of  Bell),  conuuunicating,  and  supra-scapular  nerves. 

The  nerve  to  the  subclavius  muscle  arises  from  tlie  trunk  formed  by  the 
liftli  and  sixth  cervical  nerves,  and  jiasses  downward  over  tlie  tliird  portion  of  the 
subclavian  artery  to  tlie  under  .surface  of  the  subclavius  muscle.  It  is  frequently 
connected  with  the  ]ihronic  nerve  at  the  lower  part  of  the  neck  by  a  filament  which 
passes  in  fronl  nf  the  subclavian  vrin. 

The  nerve  to  the  rhomboidei  muscles  arises  from  the  fifth  cervical  nerve, 


PLATE  XXXI 


Rhomboid  n. 
N,  to  Levator  anguR  Scapulae^ 
Suprascapular  n. 
Upper  subscapular 


Eighth  cervical  nerve 
Seventh  cervical  nerves 
Nerves  to  scaleni  and  Longus  colli 
Sixth  cervical  n. 
Nerves  to  scaleni  and  Longus  colli^ 
Fifth  cervical  n. 
From  fourth  cervical  n. 
Roots  of  phrenic  n. 
N.  to  subclavius        \\         \ 


External  anterior  thoracic  n 


Internal  anterfor  thoracic  n 


Musculo-cutanej}) 


Circumflex  n  * 


{Nerves  to 
Scaleni  and 
Longus  colli 


First  thoracic  n 


First  intercostal  n. 


Posterior  thoracic  n. 


Lesser  internal  cutaneous  n. 


Middle  subscapular  n. 
Internal  cutaneous  n. 
Lower  subscapular  n. 


Utnar  n 


,  Musculo-spiral  n 


Median  n 


AXILLARY  OF  BRACHIAL  PLEXUS  OF  NERVES. 
149 


PLATE  XXXII, 


Rectus  capitis 

lateralis  m. 

Rectus  capitis 

anticus  minor  m 

Posterior  belly 

digastric  m.(cut) 

Trachelo-mastoid  m. 


Carotid  tubercle 


Longus  colli  m 


Rectus  capitis 
lateralis  m. 


Obliquus  capitis 
superioris  m. 

Obliquus  capitis 

inferioris  m. 


Splenius  capitis  m. 


Rectus  capitis  anticus 
major  m. 

Levator  anguli  scapulae  m. 


PREVERTEBRAL   MUSCLES, 
152 


DISSECTIoy  OF  THE  NECK.  153 

pierces  the  middle  scalene  muscle,  and  passes  backward  beneath  the  levator  anguli 
scapuLT  muscle  to  the  uiuler  surface  of  the  rhomboidei  muscles,  which,  with  the 
levator  anguli  scapuke  muscle,  it  supplies.  It  accompanies  the  posterior  scapu- 
lar artery. 

The  nerves  to  the  scaleni  and  longus  colli  muscles  arist-  from  the  lower 
three  cervical  nrrves  near  the  intervertebral  ibnunina. 

The  posterior  or  long  thoracic  nerve  (external  respiratory  nerve  of  Bell) 
arises  within  the  substance  of  the  scalenus  medius  muscle  from  the  fifth,  sixth,  and 
seventh  cer\-ical  ni'rves.  The  first  two  roots  pierce  the  scalenus  medius  muscle 
below  the  nerve  to  the  rhomboidei  muscles,  and  the  last  root  passes  in  front  of  the 
scalenus  medius  muscle.  The  long  tlioracic  nerve  passes  downward  behind  the 
trunks  of  the  axillary  plexus  and  tlie  subclavian  vessels,  and  enters  tlie  axilla  Ity 
way  of  the  apex.     Here  it  lies  upon  the  serratus  magnus  muscle,  which  it  supplies. 

Communicating. — Usually  a  branch  from  the  fifth  cervical  nerve  joins  the 
phrenic  nerve  on  the  anterior  scalene  muscle. 

Tiie  supra-scapular  nerve,  tlie  largest  of  the  branches  given  off  above  the 
clavicle,  arises  from  the  upper  cervical  trunk  near  the  nerve  to  the  sulxdavius  mus- 
cle. It  passes  downward  and  outward  beneath  the  traiaezius  and  the  posterior  belly 
of  the  omo-hyoid  muscle  to  the  upper  border  of  the  scapula,  where  it  is  in  relation 
with  the  supra-scapular  artery.  It  passes  through  the  supra-scapular  notch,  being 
separated  from  the  artery  by  the  transverse  ligament,  and  enters  the  supra-spinous 
fossa.  It  supplies  the  supra-spinatus  muscle,  winds  around  the  base  of  the  spine 
of  the  scapula,  and  sends  articular  liranches  to  the  shoulder-joint,  after  which  it 
terminates  in  the  infra-spinatus  muscle. 

The  scalene  muscles. — The  scalene  muscles  are  three  in  number :  the 
anterior,  the  middle,  and  the  posterior. 

Tlie  anterior  scalene  muscle  arises  from  the  anterior  tul)ercles  of  the  trans- 
verse processes  of  the  third,  fourth,  fifth,  an<l  sixth  cervical  vertcbnc,  and  is 
inserted  into  the  tubercle  on  the  inner  border  and  upper  surface  of  the  first  ri1)  in 
front  of  the  groove  for  the  subclavian  artery.  It  is  most  deeply  situated  below. 
In  relation  with  its  anterior  surface  are  the  jjhrenic  and  pneumogastric  nerves,  the 
transversalis  colli,  .supra-scapular,  and  ascending  cervical  arteries,  the  internal 
jugular  and  suliclavian  veins,  the  subelavius  and  omo-hyoid  nmscles,  and  the 
clavicular  head  of  the  sterno-mastoid  muscle.  On  the  left  side  the  thoracic  duct 
crosses  in  front  of  the  muscle.  Along  the  inner  border  of  the  muscle,  above, 
lies  the  rectus  capitis  anticus  major  muscle ;  the  vertebral  artery  and  vein,  the 
inferior  thyroid  artery  and  sympathetic  nerves,  which  separate  it  from  the 
longus  colli  muscle,  lie  along  the  inner  side  of   the  lower    jiart    of  the  muscle. 


154  SURGICAL  ANATOMY. 

Behind  the  anterior  scalene  muscle  are  the  pleura,  the  subclavian  and  superior 
intercostal  arteries,  the  nerves  forming  the  axillary  plexus  of  nerves,  and  the 
middle  scalene  muscle. 

Nerve  Supply. — From  the  anterior  primary  branches  of  the  fourth,  fifth,  and 
sixth  cervical  nerves. 

Action. — The  anterior  scalene  muscle,  when  acting  from  its  points  of  origin, 
will  raise  the  first  rib  ;  but  if  the  ril:)  be  fixed,  the  muscle  acting  from  below  will 
flex  the  lower  cervical  vertebra?,  at  the  same  time  slightly  rotating  these  vertebrae. 

The  middle  scalene  muscle,  the  largest,  as  well  as  the  longest,  of  the  three 
scalene  muscles,  arises  from  the  posterior  tubercles  of  the  transverse  processes 
of  the  lower  six  cervical  vertebrae,  and  is  inserted  into  the  upper  surface  of  the 
first  rill,  behind  the  groove  for  the  subclavian  artery.  It  is  separated  from 
the  anterior  scalene  muscle  l)v  the  subclavian  artery  and  the  nerves  forming  the 
axillary  plexus.  Passing  through  its  substance  is  the  posterior  or  long  thoracic 
nerve  (the  external  respiratory  nerve  of  Bell).  It  is  in  relation,  in  front,  with  the 
cervical  and  brachial  plexuses  of  nerves,  the  subclavian  artery,  the  anterior  scalene, 
omohyoid,  ami  sterno-mastoid  muscles,  and  the  clavicle  ;  along  its  outer  border, 
with  the  levator  anguli  scapuhe  and  posterior  scalene  muscles;  l)eliind,  with  a 
part  of  the  posterior  scalene  and  the  deep  lateral  muscles  of  the  back  of  the  neck. 

Nerve  Supply. — From  the  posterior  jjrimary  branches  of  the  cervical  nerves. 

Action. — When  acting  from  above,  the  middle  scalene  muscle  elevates  the  first 
rib ;  with  the  rib  fixed,  it  laterally  flexes  the  cervical  portion  of  the  spinal  column. 

The  posterior  scalene  muscle,  the  smallest  and  deepest  of  the  three  scaleni, 
arises  from  the  posterior  tubercles  of  the  transverse  processes  of  the  lower  two  or 
three  cervical  vertebra?,  and  is  inserted  into  the  outer  surfoce  of  the  second  rib 
behind  the  origin  of  the  serratus  magnus  muscle.  It  is  sometimes  blended  with 
the  middle  scalene  mu.scle. 

Nerve  Supply'. — From  the  lower  three  cervical  nerves. 

Action. — It  produces  lateral  cervical  flexion  when  acting  from  below,  and 
raises  the  second  ril)  when  acting  from  above. 

The  scaleni  are  accessory  muscles  of  respiration  ;  this  can  be  demonstrated  by 
placing  the  fingers  over  them  while  taking  a  full  breath,  when  they  will  be  felt 
contracting. 

The  scalene  tubercle,  or  the  tubercle  on  the  first  rib,  to  which  the  anterior 
scalene  muscle  is  attached,  is  an  inijiDrtnnt  guide  in  locating  the  outer  edge  of  the 
muscle  and  the  tliinl  portion  of  the  subclavian  artery.  Immediately  to  the  outer 
.side  of  the  tubercle  the  sulx'lavian  artery  can  be  compressed  against  the  first 
ril).  The  position  of  the  phrenic  nerve  on  the  anterior  scalene  muscle,  and 
the  relation  which  the  clavicular  head  of  the  sterno-mastoid  muscle  holds  to  the 


DISSECTFOX  OF  THE  NECK.  155 

phrenic  nerve  and  anterior  scalene  muscle  must  be  borne  in  mind  in  operations 
upon  the  lower  part  of  the  side  of  the  neck. 

To  fiinuUze  the  diaphragm  in  suspended  respiration,  one  pole  of  the  battery 
should  lie  placed  over  the  anterior  scalene  muscle  to  stimulate  the  phrenic  nerve. 
The  head  should  be  turned  to  the  opposite  side,  so  that  the  posterior  border  of  the 
sterno-mastoid  muscle  will  not  extend  so  far  beyond  the  phrenic  nerve.  The 
author  doubts  if  this  procedure  is  of  any  value. 

Dissection. — Divide  the  trachea,  esophagus,  common  carotid  artery,  internal 
jugular  vein,  the  pneumogastric,  sympathetic,  and  recurrent  laryngeal  nerves  at 
the  lower  part  of  the  neck.  Separate  these  structures  from  the  prevertebral  mus- 
cles with  the  fingers.  In  order  to  study  the  prevertebral  muscles  and  the  pharynx, 
it  is  necessary  to  divide  the  skull  so  as  to  leave  its  posterior  portion  attached  to  the 
prevertebral  muscles  and  its  anterior  portion  attached  to  the  pharynx.  Draw  the 
pharynx  well  forward  ;  while  an  assistant  holds  a  weight  or  block  again.st  the 
upper  surface  of  the  basilar  process  of  the  occipital  bone,  divide  that  proce,ss 
between  the  attachments  of  the  pharynx  and  the  rectus  capitis  anticus  major 
nuiscle  with  a  cliisel  and  a  mallet.  The  chisel  sliould  be  directed  upward  and 
liackward.  Next  saw  through  the  sides  of  the  skull,  so  as  to  leave  the  jugular 
foramina  and  cai'otid  canals  in  the  anterior  segment.  With  a  chisel  separate  the 
petrous  portion  of  the  temporal  bone  from  the  basilar  process.  The  two  portions 
of  the  skull  can  now  be  separated  i\'ith  a  knife ;  the  two  segments  can  also  be 
separated  by  sawing  from  above  downward  just  in  front  of  the  foramen  magnum. 
The  anterior  portion  of  the  skull,  with  the  pharynx  and  larynx,  should  be  kept 
moist  wliile  the  pre\-ertebral  muscles  are  dissected. 

Dissection. — The  remainder  of  the  prevertebral  fascia  should  now  be  removed. 

The  prevertebral  muscles  are  the  longus  colli,  rectus  capitis  anticus  major, 
rectus  capitis  anticus  minor,  and  rectus  capitis  lateralis. 

The  longus  colli  muscle  consists  of  three  sets  of  fibers  :  a  longitudinal,  a  supe- 
rior oblique,  and  an  inferior  ol)li(jue  set.  The  longitudinal  set  arises  from  the 
bodies  of  the  first,  secoml,  iind  tliii'd  thoracic,  and  of  the  sixth  and  .seventh  cervi- 
cal vertebrae,  and  passes  upward  to  l)e  in.serted  into  the  bodies  of  the  second,  thii'd, 
and  fourth  cervical  vertebrfe.  The  superior  oblique  set  arises  from  the  anterior 
tubercles  of  the  transverse  processes  of  the  third,  fourth,  and  fifth  cervical  verte- 
brfe, and  passes  upward  and  inward  to  be  inserted  into  the  anterior  tubercle  of  the 
atlas.  The  inferior  oblique  set  ari.ses  from  tlie  bodies  of  the  first,  second,  and  third 
thoracic  vertebrre,  and  passes  upward  ami  outward  to  be  inserted  into  the  anterior 
tubercles  of  the  transverse  processes  of  the  fifth  and  sixth  cervical  vertebrae. 

Lying  in  front  of  the  longus  colli  muscle  are  the  prevertebral  fascia,  the 
pharynx,  the  esophagus,  the  sympathetic  nerve,  the  inferior  thyroid  artery,  the 


156  SURGICAL  ANATOMY. 

recurrent  larj'iigeal  nerve,  and  the  carotid  sheath,  containing  the  pneumogastric 
nerve,  common  carotid  artery,  and  internal  jugular  vein.  Behind  the  muscle  are 
the  cervical  and  upper  thoracic  vertebrae  and  the  vertebral  artery.  Below,  the 
vertebral  artery  lies  along  the  outer  border  of  the  muscle,  in  the  groove  between  it 
and  the  scalenus  anticus  muscle. 

Nerve  Supply. — From  the  anterior  In-anches  of  the  lower  cervical  nerves. 

Action. — It  flexes  the  cervical  jiortion  of  the  spinal  column,  slightly  flexes  it 
laterall}',  and  rotates  it. 

The  rectus  capitis  anticus  major  muscle  arises  from  the  anterior  tubercles  of 
the  third,  fourth,  fifth,  and  sixth  cervical  vertebrse  by  four  tendinous  slips ;  these 
slips  pass  upward  and  inward  to  the  belh^  of  the  muscle,  which  is  inserted  into  the 
basilar  process  of  the  occipital  bone  by  a  short  tendon. 

In  front  of  the  muscle  are  the  prevertebral  fascia,  the  common  and  internal 
carotid  arteries,  the  -internal  jugular  vein,  the  pneumogastric  and  sympathetic 
nerves,  and  a  portion  of  the  pharynx.  Behind  it  are  the  rectus  capitis  auticus 
minor  and  part  of  the  longus  colli  muscle,  and  the  upper  cervical  vertebrse. 

Nerve  Supply. — From  the  first  and  second  cervical  nerves. 

Action. — It  flexes  the  head  and  rotates  the  face  to  the  same  side. 

Dissection. — Divide  the  rectus  capitis  anticus  major  muscle  near  the  basilar 
process  and  reflect  it  downward  to  expose  the  rectus  capitis  anticus  minor  muscle. 

The  rectus  capitis  anticus  minor  muscle  arises  from  the  anterior  part  of  the 
lateral  mass  and  the  root  of  the  transverse  process  of  the  atlas.  Its  fibers  pass 
upward  and  inward  to  be  inserted  into  the  basilar  process  of  the  occipital  bone, 
between  the  foramen  magnum  and  the  insertion  of  the  rectus  capitis  anticus  major 
muscle,  which  lies  in  front  of  it.     Behind  it  is  the  occipito-atlantal  joint. 

Nerve  Supply. — From  the  first  cervical  nerve. 

Action. — It  flexes  the  head. 

The  rectus  capitis  lateralis  muscle  is  seen  to  tlie  outer  side  of,  and  slightly 
posterior  to,  the  rectus  capitis  anticus  minor  muscle.  It  arises  from  the  U2:)per 
surface  of  the  transverse  process  of  the  atlas,  and  is  inserted  into  the  jugular 
process  of  the  occipital  bone.  ' 

In  front  of  it  are  the  internal  juguLir  vein  and  the  anterior  bi'anch  of 
the  first  cervical  nerve,  and  behind  it  are  the  trachelo-mastoid  muscle  and  the 
vertebral  artery.     The  occijiital  arterj'  lies  on  its  outer  side. 

Nerve  Supply. — Fi-om  the  anterior  Itraneh  of  the  first  cervical  nerve. 

Action. — It  flexes  the  head  laterally. 

There  are  three  bursae  in  the  neck  :  one  in  front  of  the  upper  part  of  the 
thyroid  cartWage,  ov  ponium  Aclmiii ;  another  between  the  upper  margin  of  the 
thyroid  cartilage  and  the  posterior  surface  of  the   hyoid  bone  ;  a  third  is  also  situ- 


PLATE  XXXIll, 


Parotid    lymphatic  glands 


Occipital    lymphatic  glands 

Posterior  auricular 
lymphatic  glands 


Submaxillary  lymphatic 
glands 

Deep  cervical    lymphatic 
glands    covered    by 
sterno-mastoid  m 


•S^!?SS^ii^ 


Infraclavicular    lymphatic  gland 


LYMPHATIC  CLANDS  ANO  LYMPHATIC  VESSELS. 
J  57 


DISSECTION  OF  THE  XECK.  159 

atfil  lu^ar  tlie  nu'ilian  liiK',  ln'twocii  the  ^■enio-hyoicl  and  gfiii(i-liyo-glof*sus  muscles. 
TIr'sc  liursa'  may  become  enlarged  ;  that  beneath  the  geniodiyciid  muscle,  when 
distended,  may  simulate  a  ranula.  Like  goiters  and  cysts  of  the  tliyrdiil  gland, 
they  move  with  the  larynx  in  deglutitiou,  diflering  in  tliis  respect  from  sel)aeeous 
and  dermoid  cysts,  aneurysms  of  the  carotid  arteries,  and  growths  of  the  lymphatic 
glands. 

LYMPHATIC  GLANDS  OF  THE  NECK. 

The  lymphatic  glands  of  the  neck  are  classified  as  sujjerficial  and  deep. 

The  Superficial  Lymphatic  Glands  of  the  neck  are  most  numerous  along  the 
course  nf  tlie  external  jugular  vein  and  posterior  jugular  vein.  This  set,  the 
superficial  cervical  chain,  is  comj^osed  of  from  four  to  six  glands,  and  lies  beneath 
the  superficial  layer  of  the  deep  cervical  fascia  in  tlie  posterior  triangle.  The 
glands  of  this  set  are  most  numerous  at  the  lower  jiart  of  this  triangle.  Other 
small  superficial  lymphatic  glands  are  seen  in  the  median  line  of  the  neck  :  one 
below  the  symphysis  of  the  lower  jaw,  two  above  the  body  of  the  hyoid  bone,  one 
near  the  cricoid  cartilage,  one  above  the  sternum,  and  some  resting  upon  the 
trapezius  muscle.  The  superficial  cervical  chain  receives  the  efferent  vessels  from 
the  suboccipital  an<l  posterior  auricular  lymphatic  glands  and  some  from  tlie 
parntid  and  submaxillary  lymphatic  glands,  and  the  lymphatic  vessels  from  the 
external  ear  and  skin  oi'  tlie  neck.  Their  efferent  vessels  empty  into  the  inferior 
deep  cervical  glands.  The  lowest  of  the  superficial  cervical  lymphatic  glands 
also  receive  lymphatic  vessels  from  the  infraclavicular  glands  which  are  situated 
in  tlie  upper  part  of  the  delto-pectoral  sulcus.  In  secondary  syi^hilis  the  super- 
ficial cervical  lymphatic  glands  along  the  posterior  border  of  the  sterno-mastoid 
muscle  are  enlarged  early  and  can  readily  be  felt. 

The  Deep  Lymphatic  Glands  of  the  neck  number  from  twenty  to  thirty,  and 
arc  situated  alimg  the  internal  jugulnr  and  subclavian  veins.  They  are  divided 
into  a  superior  and  an  inferior  set.  Tlie  superior  set  is  situated  along  the  internal 
jugular  vein,  between  the  base  of  the  skull  and  the  bifurcation  of  the  common 
carotid  artery.  Tliese  glands  receive  the  efferent  ves-sels  from  the  internal  max- 
illary lymphatic  glands,  and  .some  from  the  sulmiaxillary  lymphatic  gland.s,  the 
lymphatic  vessels  from  the  cranial  cavity,  the  dee})  nmscles  of  the  upper  jiart  of 
tiie  neck,  the  posterior  part  of  the  tongue,  the  middle  portion  of  the  pharynx,  the 
upper  part  of  the  larynx,  and  the  upper  part  of  the  thyroid  body.  Their  efferent 
vessels  empty  into  the  glands  of  the  inferior  set.  The  inferior  set  is  situated 
along  the  internal  jugular  vein,  below  the  I)irureatiiiii  of  the  common  ennitid 
artery,  and  extends  outward  into  the  su!)clavian  triangle  along  the  subclavian 
vein.     These  elands  receive  the  efferent  vessels  from  the  superior  deep  cervical 


160  SURGICAL  ANATOMY. 

and  the  superficial  cervical  glands  ;  tlie  lymphatic  vessels  from  the  luwcr  part  of 
the  thyroid  body,  lower  part  of  the  larynx,  lower  part  of  the  pharynx,  upper  part 
of  the  trachea  and  esophagus,  and  lower  part  of  the  neck  ;  and  some  of  the 
lymj)hatic  vessels  from  the  axillary  and  infra-clavicular  glands.  Their  efferent 
vessels  unite  to  form  the  jugular  lymphatic  trunk,  which  empties  into  the  right 
lymphatic  duct  on  the  right  side,  and  into  the  thoracic  duct  on  the  left  side. 

The  deep  cervical  lymphatic  glands  are  more  important  surgically  than  the 
superficial  glands.  These  deep  glamls  hold  so  close  a  relation  to  the  great  vessels 
of  the  neck  that  an  attempt  to  remove  them  when  they  are  much  enlarged  may 
lead  the  operator  into  dangerous  locations. 

In  the  most  radical  operation  for  excision  of  the  jnammary  gland  for  carci- 
noma the  lymphatic  glands  in  the  subclavian  triangle  are  removed  so  that  there 
will  be  less  likelihood  of  recurrence  of  the  disease. 

The  right  lymphatic  duct  is  a  short  trunk  aliout  one-half  of  an  inch  in  length. 
It  receives  the  lymphatic  vessels  from  the  right  side  of  the  neck,  right  upper 
extremity,  right  side  of  the  thorax,  and  upper  surface  of  the  liver.  It  empties 
into  the  subclavian  vein  or  the  internal  jugular  vein  at  the  junction  of  these  veins. 
Its  orifice  is  guarded  by  a  double  valve. 

The  thoracic  duct,  wliich  is  described  witli  the  contents  of  the  thorax,  receives 
the  lymphatic  vessels  from  al)Out  three-fourths  of  the  body — from  the  left  side  of 
the  head,  neck,  and  thorax,  left  upper  extremitj^,  abdomen,  and  lower  extremities. 
It  is  found  only  on  the  left  side  in  the  neck.  It  emerges  from  the  upper  opening 
of  the  thorax  behind  and  internal  to  the  apex  of  the  left  pleural  sac,  curves 
forward  and  outward  above  the  first  portion  of  the  left  subclavian  artery  and  in 
front  of  the  left  vertebral  artery,  and  empties  into  the  left  subclavian  vein  or  the 
left  internal  jugular  vein  near  the  angle  of  junction  of  these  veins.  The  thoracic 
duct  near  its  termination  may  subdivide  into  two  or  more  ducts,  and  it  rarely 
empties  into  the  right  subclavian  vein. 


LIGATIOX  OF  ARTERIES  OF  HEAD  AND  NECK. 

The  innominate  artery  has  been  ligatured  twenty-four  times,  with  but  two 
recoveries  (Asldnu'st).  The  operation  is,  for  this  reason,  rarely  performed.  Liga- 
tion was  indicated  in  these  cases  by  aneurysms  of  the  right  subclavian  or  comnion 
cariilid  artery.  Di'atli  was  caused  by  secondary  hemoi'rliage  occurring  on  the 
disia]  side  nf  llu'  ligature.  To  avoid  this  sequel,  ligatures  should  be  placed  at  the 
same  time  upon    the    connnon  carotid  and  verteln'al  arteries  and   not   upon   the 


PLATE  XXXIV, 


External  carotid  a 
Inferior  dental  n 
Facial  n. 


Spinal  accessory 
anterior  to  sterno-mastoi 


Spinal  accessory  n.  poste 
mastoid  m.  and  superfic' 


First  portion  of  lingual  a. 
Facial  a. 

Second  portion  of  lingual  a. 


Superior  thyroid  a. 


Common  carotid  a.  in 
superior  carotid  triangle 


Common  carotid  a.  in 
inferior  carotid  triangle 


3d  portion  of  subclavian  a 


Innominate  a. 


LINES  OF  INCISIONS  FOR  OPERATIONS  ON   NERVES  AND  ARTERIES  OF  HEAD  AND   NECK, 
s-         ii-ii  161 


I 


PLATE  XXXV. 


Verte'rjral  a 
Pneumogastric  n. 

Clavicular  head  of  sterno-mastoid  m, 

Sternohyoid  m. 


Sternal  head  of  sterno-mastcid  ni 


SLerno-thyroid  nri. 
Thyroid  body 

Anterior  Jugular  v. 
Inferior  thyroid  veins 


Skin 
Superficial  fascia 

Superficial  layer  of  deep  fascia  and  platysnna  myoides  m' 

Internal  jugular  v 
First  portion  cf  subclavian  a' 
Ccrr.mcn  carotid  a 
Recurrent  laryngeal  n' 

Innominate  a, 

Trachea 


Comrnunicating    vein 
between  anterior  jugular 
veins 


EXPOSURE  OF  INNOMINATE  ARTERY. 
164 


I.KlArWN  OF  ARTERIES  OF  HEAD   AND  NECK. 


1()5 


inniiiuiuate  artery.  In  IVont  of  tlir  iiiiiinninato  artory  are  tlio  slci-iiuiii,  i'ii;lit 
stenio-clavicular  joint,  sterno-liyoid  and  i^turnu-thyroid  muscle.s,  ami  the  remains 
of  tlic  ^liynuis  gland.  The  left  innominate  vein  crosses  it  at  its  origin,  and  the 
right  inferior  thyroid  vein  descends  oldiqnely  over  its  lower  and  inner  jiart. 
Behind  it  are  the  trachea  and  right  pleura.  To  its  right  side  are  the  right 
imiominate  vein,  right  jmeuniogastric  nerve,  and  pleura.  To  its  left  side  are 
the  inferior  tiiyi'oiil  veins,  left  connuon  carotid  artery,  remains  of  the  tliynuis 
gland,  and,  at  its  upper  end,  the  trachea.  The  innominate  artery  divides  most 
frequently  at  the  upper  border  of  the  riglit  sterno-clavicular  articulation  ;  it 
occasionally  divides  lower,  but  seldom  higher.  Its  depth  and  relation  to  import- 
ant and  delicate  structures  render  the  operation  of  ligation  a  dillicult  one.     The 


nicision  siu) 


uld 


carried  along  the  anterior  border  of  the  right  sterno-mastoid 
muscle  to  the  upper  margin  of  the  sternum,  and  thence  along  the  riglit  clavit'le. 
An  angular  incision  is  thus  made,  each  part  of  which  should  be  about  three 
inches  in  length.  The  superficial  incision  divides  tlie  skin,  su]i(M-ficial  fascia, 
platysma  myoides  muscle,  and  supra-.sternal  and  supra-clavicular  liranchesof  the 
cervical  plexus.  The  triangular  Ihip  of  skin,  superficial  fascia,  and  platysma 
myoides  mu.scle  should  next  l)e  turned  upward.  The  superficial  layer  of  the 
deep  fascia,  sterno-hyoiil,  sterno-thyroid,  and  inner  part  of  the  sterno-mastoid 
muscle  are  next  divided.  The  anterior  jugular  vein,  Avhich  may  recpiire  division 
between  ligatures,  runs  transversely  under  the  lower  end  of  the  sterno-mastoid 
muscle.  The  sheath  of  the  common  carotid  artery  should  be  opened  and  the 
artery  traced  downward  to  the  innominate  artery.  The  aneurysm  needle,  directed 
slightly  downwai'd,  should  be  carefully  passed  around  the  artery,  from  without 
inward.  In  doing  this,  tlie  dangers  to  be  guarded  against  are  ])unc-tures  of  the 
innominate  vein  and  jdeura. 

Coll.1lTER.a.l  Circulatiox. — The  collateral  circulation  is  established  by  the 
following  anastomoses  : 


Pkoxim.vl. 


Aortic  intercostal  arteries 


Phrenic  artery  "| 

Deep  epigastric  artery  J 

Thyroidea  inia  artery 


with 

witli 
with 


Distal. 
Superior  intercostal  artery. 
Internal  mannnary  artery. 
Superior  thoracic  artery. 
Long  tlioracic  artery. 
Subscapular  artery. 
Posterior  scapidar  artrry. 

Internal  niaiiUHary  artery. 

(  Superior  thyroid  artery. 
I  Inferior  thyroid  artery. 


166  SURGICAL  ANATOMY. 

Arteries  of  one  side  of  the  head  and  neck  anastomose  with  corresponding 
arteries  of  the  opposite  side,  as  the  two  external  carotid,  two  internal  carotid,  two 
vertebral,  two  inferior  thyroid  arteries,  etc.  • 

Irregular  Forms. — The  innominate  artery  may  bifurcate  higher  or  lower 
than  the  upper  margin  of  the  right  sterno-clavicular  articulation  ;  it  may  give  off 
the  thyroidea  ima,  vertebral,  or  internal  mammary  artery,  a  thymic,  tracheal, 
broneliial,  or  pericardiac  branch,  and  it  may  arise  as  tlio  tliird  l)i'ancli  of  the 
transverse  portion  of  the  arch  of  the  aorta.  When  the  innominate  artery  bifur- 
cates at  an  unusually  high  level,  it  may  be  tied  more  readily,  and  may  overlie  the 
trachea  for  an  inch  above  the  sternum  and  be  endangered  in  the  low  operation  for 
tracheotomy  ;  if  it  divide  at  a  lower  level,  it  is  tied  with  greater  difficulty.  When 
the  innominate  artery  is  the  last  branch  of  the  transverse  portion  of  the  arch  of 
the  aorta,  it  may  pass  behind  the  trachea  and  esophagus.  An  innominate  artery 
rarely  exists  on  the  left  side,  or  the  innominate  artery  may  be  absent  and  the 
right  common  carotid  and  the  right  subclavian  artery  may  arise  from  the  arch  of 
the  aorta. 

Guides. — The  guides  to  the  innominate  artery  are  the  right  sterno-clavicular 
articulation,  the  right  common  carotid  artery,  and  the  angle  between  the  roots  of 
the  right  common  carotid  and  the  right  subclavian  artery. 

The  subclavian  artery  is  usually  tied  at  its  third  portion,  Avhich  is  to  the 
outer  side  of  the  anterior  scalene  muscle,  and  is  the  place  of  election.  Ligature 
of  the  first  portion  of  the  artery  is  attended  by  great  risk,  this  portion  being  deeply 
placed,  and  having  closely  associated  with  it  the  pneumogastric  and  symjmthetic 
nerves  and  their  cardiac  branches  ;  the  pleura  is  behind  and  the  commencement  of 
the  innominate  vein  or  the  termination  of  the  internal  jugular  vein  in  front  of 
the  first  portion.  The  scco)ul  portion  is  seldom  tied,  the  artery  being  here  covered 
by  the  anterior  scalene  muscle,  Avhicb  underlies  the  pln-enic  nerve ;  this  portion 
is  closely  related  to  the  pleura. 

The  third  portion  of  the  subclavian  artery  is  more  accessible,  being  more 
superficial,  and  not  so  closely  associated  with  important  structures.  It  is  ligatured 
for  aneurysm  of  the  arch  of  the  aorta,  the  innominate,  and  the  axillary  arterj^ ; 
also  previous  to  excision  of  the  scapula,  amputation  at  the  shoulder-joint,  and 
removal  of  large  growths  from  the  axilla.  It  is  covered  by  the  skin,  superficial 
fascia,  platysma  myoides  muscle,  supra-clavicidar  branches  of  the  cervical  plexus, 
superficial  layer  of  the  deep  cervical  fa.scia,  areolar  tissue  and  f\it,  which  here 
contains  llie  terminations  of  the  external  jugvdar  vein  and  supra-scajmlar  vein, 
and,  at  times,  tlie  jiosterior  external  jugular,  transversalis  colli,  and  jugulo-cephalic 
veins.  When  all  of  tlie.se  veins  are  present  in  this  location,  they  form  a  ])Iexus 
over  the  artery  and   increase    the    difticultv  of  reaching    the  vessel.     The    tliird 


PLATE  XXXVI. 


Superficial  layer  of  deep  fascia      Prevertebral  fascia 


Platysma  myoides  m 
Superficial  fascia 


Suprascapular  v. 

External  jugular  v. 


Deep  fascia  over  trapezius  m. 

Suprascapular  ri. 

Brachial  plexus  (n.) 


Deep  fascia  over  sterno- 
mastoid  m. 


Platysma  myoides  m. 
Subclavian  a. 


EXPOSURE  OF  THIRD  PORTION  OF  SUBCLAVIAN  ARTERY. 
167 


LIGATIOX  OF  ARTERIES  OF  HEAD   AXD  NECK.  IC!) 

jxirtit.ni  dl'  the  artery  is  also  coverL'd  by  the  ])revertebral  fascia  or  posterior 
process  of  tlie  deep  cervical  fascia,  and  is  crosstnl  \>y  liie  nerve  to  the  subclavius 
muscle.  Tlie  supra-scapular  artery  and  vein  cross  this  portion  of  the  artery 
from  within  i)ut\vard,  and  usually  lie  near  the  level  of  the  upper  border  of  the 
clavicle.  In  this  respect  the  supra-scapular  artery  bears  the  same  relation  to  the 
subclavian  artery  at  the  i)oint  of  election  as  the  middle  sterno-mastoid  artery 
does  to  the  common  carotid  artery  at  its  point  of  election.  Behind  this  part  of 
th(>  artery  are  the  middle  scalene  muscle,  the  first  rib,  and  tlu^  lower  cervical 
trunk  of  the  brachial  plexus,  which  is  formed  by  the  eighth  cervical  and  the  first 
thoracic  nerve.  Above  it  are  the  upper  and  middle  trunks  of  the  brachial 
plexus  and  the  posterior  belly  of  the  omo-hyoid  muscle.  The  upper  cer\'ical 
trunk  uf  the  l.)rachial  jilexus,  which  lies  just  above  the  artery  and  in  an  anterior 
l>lane,  may  be  mistaken  for  the  subclavian  artery.  Below,  it  rests  against  the 
upper  surface  of  the  first  rib.  The  subclavian  vein  lies  below  the  subclavian 
artery,  but  on  an  anterior  plane,  and  is  usually  behind  the  clavicle. 

In  ligating  the  tliird  portion  of  the  subclavian  artery  the  upper  part  of  the 
thorax  should  be  elevated  bj'  placing  a  pillow  beneath  the  shoulders ;  the  neck 
should  be  extended,  and  the  head  turned  toward  the  opposite  side.  The  shoulder 
is  next  depressed,  to  make  the  subclavian  triangle  shalloAV,  and  to  bring  the  artery 
nearer  to  the  surface.  The  skin  should  be  drawn  downward  over  the  clavicle,  and 
a  transver.se  incision,  three  inches  long,  should  be  carried  along  that  bone,  so  that 
when  the  skin  is  allowed  to  retract,  the  incision  will  be  about  one-half  of  an  inch 
above  the  clavicle.  This  method  of  dividing  the  skin  obviates  the  danger  of 
injuring  the  external  jugular  vein,  which  crosses  the  artery  close  to  or  under  the 
posterior  border  of  the  sterno-mastciid  nniscle.  The  incision  should  extend  from 
the  trapezius  to  the  sterno-mastoid  nmscle.  It  divides  the  skin,  superticial  fascia, 
platysma  myoides  muscle,  supra-clavicular  branches  of  the  cervical  plexus,  some 
small  arteries,  and  the  jugulo-cephalic  vein,  if  present.  The  superficial  layer  of 
the  deep  fascia  is  next  divided.  If  a  plexus  of  veins  be  present,  the  veins 
should  lie  divided  Itetween  ligatures,  and  the  posterior  process  of  the  deep  fascia 
(prevertebral  fascia)  carefully  incised.  The  posterior  belly  of  the  omo-hyoid 
muscle  is  located,  and  the  posterior  border  of  the  anterior  scalene  muscle  is  found, 
and  traced  downward  to  the  scalene  tubercle  of  the  first  rib.  The  artery  may  be 
felt  pulsating  just  external  to  the  tubercle,  and  is  exposed,  together  with  the 
cer\'ical  trunks  of  the  brachial  plexus,  by  a  slight  dissection.  The  sheath  of 
the  artery  being  opened,  the  aneurysm  needle  is  passed  around  the  artery  fVoin 
before  backward  and  belnw  ujnvard,  to  avoid  the  subclavian  vein,  which  lies  below, 
but  in  an  anterior  plane.  The  needle  should  be  held  clo.se  to  the  artery,  to  avoid 
inclusion  of  the  lowest  trunk  of  the  brachial  plexus,  which  lies  behind  the  artery. 


170  SURGICAL  ANATOMY. 

The  transversalis  colli  artery  is  rarely  seen,  owing  to  its  high  position,  while  the 
supra-scapular  artery  crosses  the  subclavian  artery  just  behind  the  clavicle.  If 
either  artery  is  seen,  it  should  be  displaced,  and  not  divided;  if  the  external  jugular 
vein  causes  much  difficulty,  it  should  be  divided  between  ligatures.  In  very 
muscular  subjects  it  may  be  necessary  to  cut  through  the  posterior  part  of  the 
clavicular  origin  of  the  sterno-mastoid  muscle.  The  variations  in  the  position  of 
this  portion  of  the  artery  should  be  borne  in  mind.  It  usually  emerges  from 
beneath  the  anterior  scalene  muscle,  about  one-half  of  an  inch  above  the  clavicle, 
and  descends  abruptly  ;  it  may,  however,  lie  almost  entirely  under  the  clavicle, 
or  it  maj^  ascend  as  high  as  one  and  one-half  inches  above  the  clavicle.  It  occa- 
sionally gives  origin  to  the  posterior  scapular  artery.  That  the  ligature  has  been 
applied  to  the  subclavian  artery  instead  of  to  a  trunk  of  the  brachial  plexus  is 
proved  by  the  absence  of  the  pulse  beyond  the  ligature. 

The  Collateral  Circulation  is  established  by  the  anastomoses  of  tlie — 

Above.  Below. 

Supra-scapular  and  .  ,       Acromio-thoracic,  posterior  circum- 

Posterior  scapular  arteries  flex,  and  subscapular  arteries. 

Internal  manimarv  artery  o         •       ^i          •      i          ^i 

^,         .      .               ■  1  •  ,       buperior    thoracic,   long   thoracic, 

bupenor  intercostal  artery  with               ,      ,            ,          ,     . 

,       .    .                 ,  and  subscapular  arteries. 
Aortic  intercostal  artery 

Irregular  Forms. — The  right  subclavian  artery  arises  at  times  higher  or 
lower  than  normally,  or  may  spring  directly  from  the  transverse  portion  of  the 
arch  of  the  aorta  as  the  first,  second,  third,  or  fourth  branch.  "When  it  is  the  first 
branch,  the  first  portion  takes  the  course  of  the  innominate  artery  and  is  more 
deeply  situated  than  normally  ;  when  it  is  the  second  or  third  branch,  it  usually 
passes  under  the  common  carotid  artery  ;  and  when  it  is  the  fourth  branch,  it  may 
pass  under  the  trachea  and  esophagus,  or  between  the  trachea  and  esophagus,  and 
has  been  seen  arising  from  the  descending  portion  of  the  aorta  as  low  as  the  fourth 
thoracic  vertebra.  The  left  subclavian  artery  may  arise  from  a  short  trunk  common 
to  it  and  the  left  common  carotid  artery.  On  each  side  the  subclavian  artery  may 
pass  in  front  of  or  pierce  the  scalenus  anticus  muscle ;  the  subclavian  vein 
may  accomjjany  the  second  portion  of  tlie  subclavian  artery  through  or  under  the 
scalenus  anticus  muscle.  The  second  portion  may  lie  under  the  clavicle,  or  may 
rise  one  and  one-half  inches  above  the  clavicle.  The  third  portion  of  the  sub- 
clavian artery  frequently  gives  origin  to  the  po.sterior  scapular  artery,  and  occasion- 
ally to  the  supra-scapular  artery,  and  in  nuiscular  persons  may  be  covered  by  IJie 
sterno-mastoid  and  trapezius  muscles.  A  clavicular  origin  of  the  posterior  belly 
of  the  omo-hyoid  muscle  may  lie  in  front  of  this  ]iortion,  and  this  belly  of  the 


PLATE  XXXVII 


Circle  of  Willis 


Superficial  temporal  a. 


Intern.-J  maxillary  a. 

Occipital  a 

External  carotid  a 

Princeps  cervicis  a 

Internal  carotid  a. 

Ligature  on  common  carotid  a. 

Ascending  cervical  a 


Superior  thyroid  a. 

Vertebral  a 
Common  carotid  a. 


Acromio-thoracic  a 
Axilllary  a. 


Subclavian  a. 
-Thyroidea  ima  (a.) 


nnominate   a. 
Superior  thoracic  a. 

Vas  aberrans  (a.) 

Intercostal  arteries 
Aorta  (a.) 


Long  thoracic  a. 


Dorsalis  scapulae  a. 
bscapular  a. 


nternal  mammary  a. 
Posterior  circumflex  a. 


COLLATERAL  CIRCULATION  AFTER  LIGATION  OF  i)UDuLh/iAN  AN[ 

171 


CAROTID  ARTERIES, 


PLATE  XXXVIII, 


Common  carotid  a 


iSterno-mastoid  m. 

^Internal  jugular  v. . 
(Vertebral  v. 
/Vertebral  a. 
(Inferior  thyroid  a. 

, Scalenus  anticus  m. 

/Thyroid  axis  (a.) 

/Transversalis  colli  a. 

Posterior  belly  of  omo-hyoid  m, 
.External  jugular  v. 


Superficial  descending  branches  of  cervical  plexus 
of  nerves 


% 


Platysma  myoides  m. 
Superficial  layer  of  deep  fascia 
Prevertebral  fascia 
Suprascapular  a. 
Phrenic  n. 

Subclavian  a. (1st  portion) 
Thoracic  duct 


Sterno-mastoid  m.(cut) 


Subclavian  v. 


EXPOSURE  OF  VERTEBRAL  ARTERY  AND   INFERIOR  THYROID  ARTERY  AT  ORIGIN-LEFT  SIDE  OF  NECK, 

174 


LIGATION  OF  ARTERIES  OF  HEAD   AND  NECK.  175 

omo-hyoid  may  lie  close  to  the  elavii'ie  in  front  ol'  (he  suhelavian  arleiy.  The 
exti'inal  jugular  vein  may  cross  the  artery  at  some  distance  external  to  tlie 
posterior  horder  of  the  sterno-mastoid  muscle. 

Guides. — The  guides  to  the  third  portion  of  the  subclavian  artery  (the 
place  of  election)  are  the  most  prominent  part  of  the  clavicle  behind  which  il  lies, 
the  posterior  border  of  the  sterno-mastoid  muscle,  the  outer  border  ol'  the  inser- 
tion of  the  scalenus  anticus  muscle  into  the  scalene  tubercle  of  the  hrst  rib,  and 
the  pulsations  of  the  artery. 

The  vertebral  artery  may  be  ligatured  for  wounds,  traumatic  aneurysm,  and 
aneurysm  of  the  innominate  artery  and  arch  of  the  aorta.  Its  only  accessible 
portion  is  deeply  situated  in  the  lower  part  of  the  neck,  where  it  lies  in  the  groove 
between  the  scalenus  anticus  and  longus  colli  mu.scles.  This  portion  of  the  artery 
is  in  relation,  in  front,  with  the  vertebral  and  internal  jugular  veins,  and  is  crossed 
on  both  sides  by  the  inferior  thyroid  artery  and  by  the  thoracic  duet  on  the  left 
side.  The  vertebral  vein  crosses  in  front  of  the  artery  just  below  the  transverse 
process  of  the  sixth  cervical  vertebra ;  it  tlien  lies  in  front  and  to  the  outer  side 
of  the  artery  as  it  passes  downward  to  the  innominate  vein.  The  relation  of  this 
vein  to  the  artery  is  variable,  as  the  vein  may  be  found  on  either  side  of  the  artery. 
Behind  the  artery  are  the  sympathetic  nerve  cord,  the  inferior  cervical  sympathetic 
ganglion,  and  the  transverse  process  of  the  seventh  cervical  vertebra.  To  its 
iimer  side  is  the  longus  colli  muscle,  and  to  its  outer  side  the  anterior  scalene 
muscle.     It  is  surrounded  by  the  vertebral  sympathetic  plexus. 

In  the  operation  for  ligation  of  the  vertebral  artery  the  patient  lies  in  the 
same  position  as  in  ligature  of  the  third  j)ortion  of  the  subclavian  artery — /.  c,  with 
the  shoulder  elevated,  the  neck  extended,  and  the  face  turned  to  the  oj^posite  side. 
The  incision  should  commence  at  the  clavicle,  and  be  carried  for  three  inches 
upward  along  the  posterior  border  of  the  sterno-mastoid  muscle. 

Care  is  required  here  to  avoid  injuring  the  external  jugular  vein,  which  runs 
under  tlie  platysma  myoides  muscle  obliquely  across  the  sterno-mastoid  muscle  to 
its  posterior  border,  then  along  that  border,  piercing  the  superficial  layer  of  the 
deep  fascia  one-half  of  an  inch  above  the  clavicle.  The  incision  divides  the  skin, 
superficial  fascia,  platysma  myoides  muscle,  and  descending  branches  of  the 
cervical  plexus.  The  external  jugular  vein  is  exposed  and  drawn  outward,  and 
the  superficial  layer  of  the  deep  fascia  divided.  It  may  be  necessary  to  .sever  part 
of  the  clavicular  head  of  the  sterno-mastoid  muscle  at  its  origin.  The  anterior 
scalene  mu.scle  is  located,  and  the  surgeon  carries  his  finger  inward  through  the 
interval  between  the  prevertebral  fascia  and  the  superficial  layer  of  the  deep 
fascia.  The  positions  of  the  internal  jugular  vein,  common  carotid  artery,  and 
transverse  process  of  the  sixth  cervical  vertebra  are    ascertained.     The    anterior 


176  SURGICAL   ANATOMY. 

tubercle  of  the  transverse  process  of  the  sixth  cervical  vertelji'a  (carotid  hihcrclc) 
is  the  guide  to  the  vertebral  artery,  fur  the  reason  that  it  is  usually  the  first 
transverse  process  which  is  entered  by  the  artery.  Just  below  this  tul)ercle  the 
groove  between  the  scalenus  anticus  and  longus  colli  muscles  can  be  felt,  and  the 
prevertebral  fascia  is  divided  along  the  inner  l)orderof  the  scalenus  anticus  muscle. 
Along  tlie  inner  border  of  the  scaletuis  anticus  nmscle  the  inferior  thyroid  artery 
can  be  recognized  b}'  its  jiulsations ;  the  vertebral  artery  is  detected  in  tlie  same 
manner,  deep  in  the  groove  previously  mentioned.  The  vertebral  vein  and 
inferior  thyroid  artery  should  then  be  drawn  outward,  and  the  needle  be  passed 
from  without  inward.  Care  is  necessary  to  avoid  injuring  the  internal  jugular 
vein,  inferior  thyroid  artery,  vertebral  A\'in,  pleura,  the  right  lymphatic  duct,  and, 
on  the  left  side,  the  thoracic  duct.  Tlie  phrenic  nerve  is  not  endangered,  because 
it  lies  beneath  the  prevertebral  fascia  on  the  scalenus  anticus  muscle.  Immediately 
after  the  artery  is  tied  contraction  of  the  pupil  of  the  same  side  occurs,  due  to  dis- 
turbance of  the  vertebral  plexus  of  the  sympathetic  nerve.  This  condition  is 
evidence  that  the  inferior  th^'roid  artery  or  its  ascending  cervical  branch  has  not 
been  ligatured  instead  of  the  vertebral  arteiy. 

Irregular  Forms. — The  left  vertebral  artery  may  arise  from  the  subclavian 
artery  at  a  point  unusually  near  either  to  tiie  origin  or  the  termination  of  the  first 
portion  of  the  left  subclavian  artery.  It  may  arise  from  the  arch  of  the  aorta  or 
the  left  common  carotid  artery. 

The  right  vertebral  artery  occasionally  arises  nearer  to  the  bifurcation  of  the 
innominate  artery  or  to  the  inner  margin  of  the  scalenus  anticus  musck'.  A\'hen  the 
right  subclavian  artery  arises  from  tlie  aortic  arcli,  the  right  vertebral  arter}'  may 
arise  from  the  right  common  canitid  artery  or  from  the  arch  of  the  aorta.  When 
it  arises  from  the  left  side  of  the  aortic  arch,  it  may  pass  behind  the  esophagus. 

Either  vertebral  artery  may  arise  from  the  subclavian  as  two  branches,  which 
later  unite,  or  the  vertebral  artery  may  divide  while  passing  upward  in  the  trans- 
verse processes,  one  branch  entering  the  spinal  canal  with  the  second  cervical 
nerve,  and  the  otlier  pursuing  the  normal  course  of  the  vertebral  artery.  On  each 
side  the  vertebral  artery  frequently  enters  tlie  passageway  in  the  cervical  trans- 
verse processes,  at  some  other  than  at  tlie  sixth  cervical  transverse  process.  It 
may  first  enter  any  of  the  cervical  transvei'se  processes  from  the  second  to  the 
seventli  inclusive.  When  the  artery  first  enters  the  seventh  cervical  transverse 
process  its  ligation  is  difficult,  and  wlien  it  enters  above  the  sixth,  the  artery  lies 
nearer  to  the  esophagus  than  nnrinally.  The  vcrtt'bral  artery  rarely  gives  origin 
to  the  inferior  thyroid,  superior  intercostal,  jjrofunda  cervicis,  or  occipital  artery. 
One  vertebral  artery  may  be  larger  than  the  artery  of  the  ojjposite  side. 

Guides. — The  guides  to  the  vertebral  artery  are  the  posterior  border  of  the 


PLATE  XXXIX, 


Submaxillary  gland 

Hypoglossal 

Lingual  ; 

Digastric  tendO' 

Stylo-hyoid  r 


Hyoglossus  m. 


old  m. 

stric  tendon 

perficial  layer  of  deep  fascia 

Platysma  myoides  m. 


Internal  laryngeal  n 
Extornil  laryngeal  n. 

External  carotid  a. 

Superior  thyrord  a. 
Superior  thyroid  veins 


Middle  sterno-mastoid  a. 
Superficial  layer  ■  '  ■'="''  f->^^.. 
Platysma  myc; 


Superficial  layer  of  deep  fascia 
Anterior  belly  omo-hyord  m 

Thyroid  body 
Inferior  thyroid  a 

Sterno-mastoid  m 
Prevertebral  fascia 


Anterior  jugular  v. 
Branch  of  ansa  hypoglossi  (n.) 
Common  Carotid  a. 


LIGATION  OF  {])  FIRST  AND  SECOND  PORTIONS  OF  LINGUAL  ARTERY;    (2)  SUPERIOR  THYROID  ARTERY; 

(3)  INFERIOR  THYROID  ARTERY, 
177 


s— 


Jl— 12 


LIGATION  OF  ARTERIES   OF  HEAD  AXD   NECK.  179 

sterno-niastoid  muscle  and  tlie  canitiil  tubrrclo  or  aiitcrinr  tulKTcle  of  the  sixth 
cervical  transverse  process,  which  lies  at  tlic  n})per  extremity  of  tiic  groove  l)et\veen 
the  scalenus  anticus  and  longus  colli  muscles. 

The  inferior  thyroid  artery  may  be  ligatured  to  arrest  the  growth  of  the 
tlivroid  body  in  goiter,  and  for  wounds  of  this  body.  It  is  more  commonly  liga- 
tured in  the  removal  of  one-half  of  the  thyroid  body  (thyroidectomy).  It  nray 
lie  tied  near  its  origin,  where  it  lies  alimg  thi'  inner  border  of  tiie  anterior  scalene 
muscle, — i.e.,  between  that  musele  and  the  internal  jugular  vein,  or  to  the  inner 
side  of  the  carotid  sheath  as  it  enters  the  thyroid  gland.  It  is  seldom  ligatured 
near  its  origin,  where  it  may  be  secured  through  an  incision  similar  to  that 
made  in  ligature  of  the  vertebral  artery.  To  reach  it  just  before  it  enters  the 
thyroid  body,  where  it  lies  on  or  slightly  below  the  level  of  the  cricoid  cartilage  of 
the  larynx,  the  shoulders  should  be  elevated  and  the  neck  extended,  and  an 
incision  three  inches  long  be  made  along  the  lower  portion  of  the  anterior 
border  of  the  sterno-mastoid  muscle.  The  skin,  superficial  fascia,  and  platysma 
myoides  muscle  are  divided,  avoiding  the  anterior  external  jugular  vein ;  the 
superficial  layer  of  the  deep  fascia  is  also  divided.  The  sterno-mastoid  mu.scle  and 
carotid  sheath  with  its  contents  should  be  drawn  outward,  and  the  sterno-hyoid 
and  sterno-thyroid  muscles  and  tlivroid  ])ody  drawn  inward.  Locate  tlie  carotid 
tubercle  behind  the  carotid  sheath,  and  the  artery  will  be  felt  pulsating  just  below 
and  internal  to  it.  Next  divide  the  preverteljral  fascia.  The  artery  should  then 
be  tied  near  the  carotid  sheath,  thus  avoiding  injury  of  the  recurrent  laryngeal 
nerve  ;  this  nerve,  however,  is  not  in  much  danger,  as  in  this  location  it  lies 
behind  and  internal  to  the  lateral  lobe  of  tlie  thyroid  body.  The  inferior  thyroid 
artery  frequently  divides  behind  the  carotid  sheath  into  two  terminal  branches  of 
about  equal  size,  which  are  separated  by  an  interval  of  about  one-fourth  of  an  inch. 

Irregularities. — The  inferior  thyroid  artery  occasionally  arises  directly  from 
the  first  portion  of  the  subclavian  artery  ;  it  may,  however,  arise  from  the  third 
portion  near  the  outer  border  of  the  scalenus  anticus  muscle,  or  from  the  vertebral 
or  common  carotid  artery.  It  may  subdivide  before  it  reaches  tlie  thyroid  body, 
or  it  may  arise  as  two  separate  arteries,  one  branch  of  it  passing  in  front  of  and 
the  other  beliiml  the  carotid  sheath.     The  artery  maj^  be  small  or  absent. 

The  common  carotid  artery  is  tied  for  aneurysm  or  wounds  of  the  internal  or 
external  carotid  artery  or  their  branches,  to  check  malignant  growths,  and  pre- 
paratory to  the  removal  of  tumors.  It  may  be  tied  in  any  part  of  its  course  in  the 
neck,  which  is  indicated  liy  a  line  drawn  from  the  sterno-clavicular  articulation  to 
a  point  midway  between  the  angle  of  the  lower  jaw  and  the  mastoid  process  of  the 
temporal  bone,  the  portion  of  this  line  below  the  level  of  the  upper  border  of  the 
thvroid  cartilage  indicating  the  course  of  the  common  carotid  arterv.     On  the 


180  SURGICAL  ANATOMY. 

right  side  the  common  carotid  artery  arises  as  one  of  tlie  two  terminal  branches 
of  the  innominate  artery,  which  divides  behind  the  upper  border  of  the  right 
sterno-clavicular  articuUition ;  on  the  left  side,  however,  it  arises  within  the  chest 
from  the  arch  of  the  aorta.  On  both  sides  the  common  carotid  artery  terminates 
opposite  the  upper  border  of  the  thyroid  cartilage,  where  it  divides  into  the  external 
and  internal  carotid  arteries. 

In  front  of  tlie  artery  are  the  skin,  superficial  fascia,  platysma  myoides  muscle, 
superficial  layer  of  the  deep  fascia,  inner  border  of  the  sterno-mastoid  muscle,  ante- 
rior jugular  vein,  sterno-hyoid  muscle,  sterno-thyroid  muscle,  lateral  lobe  of  the 
thyroid  gland,  superior  and  middle  thyroid  veins,  middle  sterno-mastoid  artery, 
omo-hyoid  muscle,  descendens  hypoglossi  nerve,  ansa  liypoglossi,  and  anterior  wall 
of  the  sheath.  To  its  outer  side  are  the  internal  jugular  vein  and  the  pneumo- 
gastric  nerve.  On  the  right  side  the  internal  jugular  vein  at  the  root  of  tlie  neck 
passes  outward  away  from  the  artery,  while  on  the  left  side  it  overlaps  the  artery 
and  curves  forward  to  empty  into  the  left  innominate  vein.  Behind  and  to  its  outer 
side  is  the  pneumogastric  nerve,  and  behind  it  are  the  posterior  wall  of  its  sheath, 
the  sympathetic  nerve,  inferior  tliyroid  artery,  recurrent  laryngeal  nerve,  and  the 
longus  colli  and  rectus  capitis  anticus  major  muscles.  To  its  inner  side  are  the 
inner  wall  of  its  sheath,  the  trachea,  esophagus,  recurrent  laryngeal  nerve,  lateral 
lobe  of  the  thyroid  gland,  cricoid  cartilage,  thyroid  cartilage,  pharynx,  superior 
thyroid  artery,  and  external  laryngeal  branch  of  the  superior  laryngeal  nerve. 

It  is  usually  tied  in  the  superior  carotid  triangle, — above  the  anterior  belly  of 
the  omo-hyoid  muscle, — where  it  is  more  superficial.  In  the  inferior  carotid  tri- 
angle— below  the  anterior  belly  of  the  omo-hyoid  muscle — the  artery  is  deeper, 
being  in  this  location  covered  by  additional  structures,  the  sterno-hyoid  and  sterno- 
thyi-oid  muscles,  and  overlapped  by  the  lateral  lobe  of  the  thyroid  gland.  The 
omo-hyoid  muscle  crosses  the  artery  at  the  level  of  the  cricoid  cartilage,  the  middle 
thyroid  vein  crosses  just  above  that  muscle,  and  the  superior  thyroid  vein  and 
middle  sterno-mastoid  artery  cross  the  artery  higher  in  the  .superior  carotid  triangle. 

In  the  operation  through  the  superior  ccmitiil  triangle  the  patient  should  rest 
upon  the  back,  with  the  shoulders  elevated,  the  neck  extended,  and  the  face  turned 
slightly  to  the  opposite  side.  The  superficial  veins  should  be  located,  especially 
the  vein  which  connects  the  submental  veins  with  the  anterior  jugular  vein  and 
runs  beneath  the  platysma  myoides  muscle  parallel  to  and  along  the  inner  side  of 
tlie  anterior  boi-dcr  of  the  sterno-mastoid  muscle.  An  incision  three  inches  long 
sliould  l)e  made  in  the  line  of  the  artery,  so  that  the  center  of  the  incision  will  be 
on  a  level  with  the  cricoid  cartilage.  Skin,  superficial  fascia,  platysma  myoides 
muscle,  superficial  vessels  and  nerves,  and  the  superficial  layer  of  the  dee])  fascia 
are  divided,  the  communicating  branch  between    the  anterior  jugular  and  sub- 


PLATE  XL 


Superficial  fascU 
Superficial  layer  of  deep  fascia 
Buccal  br.of  facia 
Supramaxillary  br.of  facial  n, 
Inferior  dental  n. 
, Inferior  dental  a. 
,Masseter  m. 
Deep  fascia 
Platysma  myoides  m. 
Superficial  fascia 

Deep  fascia 
Facial  v. 
Facial  a. 
Lower  jaw 
.Platysma  myoides  m. 


r -Superficial  layer 
of  deep  fascia 
Descendens  hypoglosi^i  n. 


rr,o-n-,astoid  a. 


Superficial  cervical  nj 
Superficial  descending  br.of  cervical  plexus  (n,) 


Anterior  belly  of  omo-hyoid  m. 
Sterno-mastoid  nn.  ' 

Incisions  into  carotid  sheath  and  true  arterial  sheath 

Ansa  hypoglossi  (n.) 
Middle  sterno-mastoirl  a. 


I 


tXPOSURE  OF  (1)  INFERIOR  DENTAL  NERVE;  (2)  FACIAL  ARTERY;   (3,  4)  SPINAL  ACCESSORY  NERVt  AND  SUPERFICIAL 
BRANCHES  OF  CERVICAL  PLEXUS;  AND  (5)  COMMON  CAROTID  ARTERY  IN  SUPERIOR  CAROTID  TRIANGLE. 

182 


PLATt  XLI, 


Hypoglossal  n 
Occlp 


Superficial  layer 
of  deep  fascia 
External  jugular  v 
Internal  jugular  v 
Sterno mastoid  m 

Bifurcatior),  of 
common  carotid  A 


External  carotid  a. 
Lingual  a. 
Facial  a. 
rnal  carotid  a. 
Facial 


Lingual  V. 

f  superior  thyroid  v. 


Superior  thyroid  a. 
Superior  thyroid  v. 


Superficial  fascia 
Superficial  layer  of  deep  fascia 
Omo-hyoid  m 
Platysma  myoides  m 
Sterno-mastoid  m 
Br. of  ans2  hypoglossi  n 

Middle  sterno-mastoid  a 


Anterior  jugular  v. 

Sheath  of  sterno-thyroid  m. 

Carotid  sheath 

Thyroid  body 
Common  carotid  a.  and  opening  in  true 
sheath 


(1)  EXPOSURE  OF  EXTERNAL  CAROTID  AND  INTERNAL  CAROTID,  AND  OF  THE  SUPERIOR  THYROID,  LINGUAL,  FACIAL, 
AND  OCCIPITAL  AT  THEIR  ORIGIN;  AND  v?)  EXPOSURE  OF  COMMON  CAROTID  IN  INFERIOR  CAROTID  IRIANCLE. 

183 


LK!  AT/OX  OF  AIITERIES   OF  UFA  I)   AND   NECK. 


185 


mental  veins  WAwix  avdiilcil.  Tlio  sterno-mastoid  must'lc  .slioulil  he  ilisplaced  out- 
wanl  anil  the  omo-hyoid  lunsele  ilDunward,  ami  tlie  })ulsations  of  the  arterv  are 
felt.  Tlie  middle  sterno-mastoid  arteiy  and  the  superior  and  middle  thyroid  veins 
sliould  he  avoided,  if  possible,  and  the  internal  jugular  vein  and  descendens  hypo- 
glossi  nerve  should  be  avoided  l)y  opening  the  inner  wall  of  the  carotid  sheafli. 
\\\  holding  up  tirst  one  edge  of  the  opening  in  the  slieath  and  then  the  other, 
the  siieath  can  he  gently  separated  from  the  artery  with  an  aneurysm  needle. 
The  needle  should  he  passed  from  without  inward,  threaded,  and  witlidrawn. 

To  tie  the  connnon  carotid  artery  in  the  inferior  carotid  Iriangle,  the  patient 
should  be  placed  in  the  same  position  as  for  the  higher  ligation.  The  incision, 
which  is  about  three  inches  in  length,  should  be  made  along  the  anterior  border  of 
the  sterno-mastoid  muscle,  beginning  at  the  level  of  the  cricoid  caVtilage,  and 
extending  almost  to  the  sterno-clavicular  articulation.  Skin,  superficial  fascia, 
platysma  myoides  muscle,  and  superficial  vessels  and  nerves  are  divided.  The 
anterior  jugular  vein  and  the  vein  which  connects  it  with  the  facial  or  submental 
vein  should  be  avoided.  The  superficial  layer  of  the  deep  fascia  is  divided,  and  the 
sterno-mastoid  muscle  drawn  outward,  the  sterno-hyoid  and  sterno-thyroid  muscles 
inward.  The  sheath  is  opened  on  tlie  inner  side,  and  the  needle  passed  from  with- 
out inward.  The  structures  which  are  to  be  avoided  in  the  operation  are  the  ante- 
rior jugular  vein  ;  its  tributary,  which  runs  beneath  the  platysma  myoides  muscle 
parallel  with  the  anterior  border  of  the  sterno-mastoid  muscle  ;  the  nerves  from  the 
ansa  hypoglossi  to  the  sterno-hyoid  and  sterno-thyroid  muscles,  the  internal  jugular 
vein,  the  inferior  thyroid  veins,  the  inferior  thyroid  artery,  and  the  recurrent 
larj'ngeal  nerve.  On  the  left  side  the  internal  jugular  vein  overlaps  the  artery  at 
the  lower  part  of  the  neck  and  renders  the  operation  more  difficult. 

Collateral  Circulation. — The  collateral  circulation,  after  ligation  of  the 
common  carotid  artery,  is  established  by  the  anastomoses  of  the  following  arteries : 


with 


Proximal  Side. 
Branches  of   the  external  carotid 
artery  of  the  opposite  side 

Vertebral  artery  of  same  side  and 

opposite  internal  carotid  artery      with 

and  vertebral  arterv 
Inferior  thyroid  arterv,  thyroidea 

ima  artery  (if  present) 
Ascending  cervical  artery 

Superficial  cervical  artery  with      Princeps  cervicis  artery. 

Deep  cervical  artery 

Ascending  cervical  artery  with      Ascending  pharyngeal  artery. 

Vertebral  artery  with      Occipital  artery. 


Distal  Side. 
Branches  of   the  external  carotid 
artery  of  the  same  side. 

Internal  carotid  arterv  of  the  same 
side  through  circle  of  Willis. 


with      Superior  thyroid  artery. 


186  SURGICAL  ANATOMY. 

The  tissues  supplied  by  the  external  carotid  arterj'  are  chiefly  nourislied 
through  the  anastomoses  between  the  opposite  branches  of  the  two  external  carotid 
arteries,  and  the  portion  of  the  brain  previously  nourished  by  the  internal  carotid 
artery  receives  its  blood  supply  through  the  two  vertebral  arteries  and  the  opposite 
internal  carotid  artery. 

Irregularities. — The  right  common  carotid  artery,  when  the  innominate 
artery  is  absent,  may  arise  from  the  arch  of  the  aorta  separately  or  from  a  tnmk 
common  to  tlie  two  common  carotid  arteries.  When  it  arises  from  a  trunk  com- 
mon to  it  and  the  left  common  carotid  artery,  it  may  cross  in  front  of  the  trachea 
above  the  sternum.  Owing  to  the  variability  in  the  level  at  whicli  the  innominate 
artery  bifurcates,  the  right  common  carotid  artery  may  arise  higlier  or  lower  than 
the  upi)er  margin  of  tlie  right  sterno-clavicular  joint ;  its  origin  is  more  frequently 
below  that  level  than  above  it. 

The  left  common  carotid  artery  varies  chiefly  in  its  origin  fi'om  the  arch  of  the 
aorta.  Its  place  of  origin  may  extend  into  that  of  the  innominate  artery.  When 
the  right  common  carotid  artery  arises  from  the  arch  of  the  aorta,  the  two  carotid 
arteries  may  arise  from  a  common  trunk.  The  left  common  carotid  artery  occa- 
sionally arises  from  a  left  innominate  artery. 

Either  of  the  common  carotid  arteries  maj'  bifurcate  higher  or  lower  than 
the  upper  border  of  the  thyroid  cartilage.  The  artery  may  bifurcate  above  the 
level  of  the  hyoid  bone,  giving  off  some  of  the  branches  which  should  arise 
from  the  external  carotid  artery.  It  may  not  bifurcate,  the  external  carotid  or 
internal  carotid  artery  being  absent.  The  point  of  bifurcation  may  be  as  low  as 
tlie  root  of  the  neck.  The  common  carotid  artery  may  be  absent,  the  external 
carotid  and  internal  carotid  arteries  arising  from  the  innominate  artery  or  the  arch 
of  the  aorta. 

The  conmion  carotid  artery  niay  give  origin  to  the  thyroidea  ima,  vertebral, 
inferior  thyroid,  or  some  of  the  branches  of  the  external  carotid  artery.  The 
pneumogastric  nerve  may  lie  in  front  of  tlie  common  carotid  artery. 

Tlie  external  carotid  artery  is  ligatured  after  injury  to  tliis  vessel  or  its 
liranclies,  to  check  malignant  growths,  in  cirsoid  aneurysm  of  its  branche.s,  before 
removal  of  tlie  parotid  gland,  and  in  various  other  conditions.  The  artery  is 
usually  tied  lietween  the  points  of  origin  of  the  lingual  and  superior  thyroid 
arteries  and  in  the  superior  carotid  triangle,  as  it  is  more  superficial  here,  and  the 
distaiu'e  from  the  bifurcation  of  the  common  carotid  artery  is  sufficient  to  favor 
tiic  formation  of  a  clot.  Its  course  is  represented  by  that  portion  of  tlie  line 
of  tlie  common  carotid  artery  whicli  is  above  the  level  of  tlii'  u))pi'r  border  of 
the  thyroid  cartilage.  In  the  superior  carotid  triangle  below  the  posterior  bell}' 
of  the  digastric  muscle  the  external   carotid   artery   is  covered    by  skin,   super- 


LIGATION  OF  ARTERIES  OF  HEAD   AND   NECK.  187 

ficial  fascia,  platysma  niyoides  imisclc,  superlk'ial  layer  of  tlie  deep  fa^ieia, 
anterior  lionler  of  tiie  stenio-niastoid  muscle,  and  the  sheath  of  the  vessels;  it  is 
crossed  by  the  hypo-glossal  nerve  and  lingual  and  laeial  veins.  Jligher  in  its 
course  it  is  crossed  by  the  stylo-hyoid  and  jiosterior  belly  of  the  digastric  muscle, 
and  enters  the  parotid  gland.  To  its  inner  side  are  the  hyoid  bone,  the  pharynx, 
the  superior  laryngeal  and  glusso-pharyngeal  nerves,  part  of  the  parotid  gland,  and 
the  ranuis  nf  the  Imver  jaw.  To  its  outer  side,  at  its  origin,  is  the  internal  carotid 
artery.  IJehind  it  are  the  internal  carotid  arteiy,  from  which  it  is  separated  above 
by  the  stylo-glossus  and  stylo-pharyngeus  muscles,  the  glosso-pharyngeal  nerve,  the 
pharyngeal  branch  of  the  pneumogastric  nerve,  the  stylo-liyoid  ligament,  and  p;irt 
of  the  parotid  gland.     The  superior  laryngeal  nerve  is  also  behind  the  arti'ry. 

The  position  of  the  patient  should  be  the  same  as  in  ligature  of  the  connnon 
carotid  artery,  the  shoulders  being  elevated,  the  neck  extemled,  and  the  face 
turned  slightly  to  the  opposite  side.  The  incision  should  exti'ud  from  the  angle 
of  the  lower  jaw  downward  along  the  anterior  l)order  of  the  sterno-niastoid 
nuiscle  for  about  two  and  one-half  inches,  so  that  the  greater  cornu  of  the 
hyoid  bone  will  be  just  above  the  center  of  the  incision.  The  skin,  su])erficial 
fascia,  platysma  myoides  muscle,  some  cutaneous  vessels  and  nerves,  and  the 
superficial  layer  of  the  deep  fascia  are  divided.  The  sterno-mastnid  muscle  is 
drawn  outward,  and  the  greater  cornu  of  tlie  hyoid  bone,  the  liypo-glossal  nerve, 
and  lingual  and  facial  veins  located.  The  sheath  is  opened,  and  the  needle  is 
passed  from  without  inward.  The  needle  should  be  kept  close  to  the  artery,  tlius 
avoiding  the  superior  laiyngeal  nerve,  which  passes  beneath  the  artery. 

Collateral  Circulation. — The  collateral  circulation,  after  ligature  of  the 
external  carotid  artery,  is  established  by  the  anastomoses  between  the  branches  of 
this  artery  and  the  corresponding  branches  of  the  opposite  external  cai-otid  artery. 

Irregularities. — The  external  carotid  artery  may  be  absent,  the  branches 
of  that  artery  arising  from  the  common  carotid  artery,  which  continues  upward 
as  the  internal  carotid  artery.  It  may  be  a  short  trunk  or  arise  at  a  higher  or 
lower  level  than  noi'mally.  Two  or  more  of  its  branches— as  the  suijcrior  thyroid, 
lingual  and  facial  arterie.s — may  arise  from  it  by  a  connnon  trunk.  Some  of  its 
lower  branches  may  arise  from  the  common  carotid  artery.  Occasionally  it  gives 
origin  to  additional  branches — viz.,  the  superior  laryngeal  and  middle  .sterno- 
mastoid  branches  of  the  superior  thyroid  artery,  the  ascending  palatine  and 
tonsillar  branches  of  the  facial  artery,  the  superior  sterno-mastoid  branch  of  the 
occipital  artery,  and  the  transverse  facial  branch  oi  the  su]ierficial  temporal  artery. 

The  superior  thyroid  artery  is  tied  prej)aratory  to  removal  of  one-half  of  the 
thyroid  body,  and  may  be  ligatured  to  arrest  the  growth  of  a  goiter.  It  arises  from 
the  external  carotid  artery  just  below  the  greater  cornu  of  the  hyoid  hone,  and  runs 


188  SURGICAL  ANATOMY. 

forward  and  then  downward  and  forward  along  the  inner  side  of  the  carotid  sheath. 
Its  upper  portion  is  superficial,  its  lower  jjortion  l)eing  more  deeply  situated 
between  the  larynx  and  the  carotid  sheath.  The  superior  laryngeal  nerve  lies 
beneath  the  upper  portion  of  the  artery,  and  its  external  laryngeal  branch  runs 
parallel  with  the  lower  part  of  the  vessel.  The  artery  may  be  tied  near  its  origin 
and  above  its  hyoid  branch,  but  is  preferably  ligatured  between  the  origins  of  the 
superior  laryngeal  and  middle  sterno-mastoid  branches. 

The  patient  is  placed  in  the  same  position  as  for  ligature  of  the  external 
carotid  artery,  and  an  incision  two  inches  long  should  be  made  along  the  anterior 
border  of  the  sterno-mastoid  muscle.  The  center  of  the  incision  should  be  on  a 
level  with  the  upper  border  of  the  thyroid  cartilage.  Skin,  superficial  fascia,  pla- 
tysma  myoides  muscle,  and  superficial  layer  of  the  deep  fascia  are  divided.  The 
sterno-ma.stoid  muscle  is  drawn  outward,  and  the  superior  thyroid  arter}'  seen  run- 
ning downward  along  the  inner  side  of  the  carotid  sheath.  The  artery  should  be 
traced  from  its  origin  and  tied  above  the  origin  of  the  middle  sterno-mastoid  artery, 
avoiding  the  superior  thyroid  vein.  The  vein  which  connects  the  facial  or  sub- 
mental vein  with  the  anterior  jugular  vein  and  runs  beneath  the  platysma  myoides 
muscle  parallel  with  the  anterior  margin  of  the  sterno-mastoid  muscle  should  also 
be  avoided.  The  needle  is  preferably  passed  away  from  the  superior  thyroid 
vein,  which  usually  runs  on  the  lower  side  of  the  artery  and  may  form  a  plexus. 

Irregularities  of  the  superior  thyroid  artery  and  of  the  other  branches  of 
the  external  carotid  artery  are  not  of  much  surgical  importance.  The  superior 
thyroid  artery  may  be  double,  or  it  may  be  unusually  small,  the  other  thyroid 
arteries  being  larger  than  normal.  It  may  arise  from  the  common  carotid  artery 
or  a  trunk  common  to  it  and  the  lingual  artery,  or  a  trunk  common  to  the  supe- 
rior thyroid,  lingual,  and  facial  arteries.  The  hyoid,  superior  laryngeal,  and 
middle  sterno-mastoid  branches  may  arise  from  the  external  carotid  artery.  The 
superior  laryngeal  artery  may  be  unusually  large,  occasionally  passing  through  a 
foramen  in  the  thyroid  cartilage,  or  it  may  pass  along  the  thyroid  cartilage  and 
turn  inward  under  the  lower  margin  of  that  cartilage.  The  crico-thyroid  artery 
may  be  unusually  large,  and  may  send  a  branch  downward  over  the  crico-thyroid 
membrane  to  the  isthmus  of  the  thyroid  body.  Such  an  abnormal  branch  would 
be  divided  in  laryngotomy  and  perhaps  in  high  tracheotomy.  For  this  reason  it 
is  advisable  to  thoroughly  expose  the  crico-thyroid  membrane  before  incising  it, 
as  the  entrance  of  blood  into  the  larynx  might  cause  broncho-pneumonia. 

Tlu'  lingual  artery  is  mo.st  frequently  ligatured  preparatory  to  removal  of  the 
tongue.  It  is  also  tied  to  control  licmorrhage  from  it  or  its  liranches  in  injuries 
and  advanced  carcinoma  of  the  tongue,  to  check  the  growth  of  advanced  carci- 
noma of  tile  tongue,  and   in  macroglossia.      It  arises  from  the  external  carotid 


LIGATIOX  OF  ARTERIES  OF  HEAD   ASD   NECK.  .  ISO 

artery,  opposite  the  greater  coriiu  of  tlu'  hyoid  hone,  and  its  course,  as  elsewhere 
described,  is  divided  into  three  portions  : 

The  first  portion  extends  from  the  origin  of  the  artery  to  the  outer  border  of 
the  hyo-glossus  muscle.  It  ascends  to  reach  the  upper  border  of  the  greater  cornu 
of  the  hyoid  bune,  and  then  runs  just  above  and  parallel  with  that  cornu.  Tiiis  is 
the  most  superficial  portion  of  the  artery.  It  is  covered  by  skin,  superficial  fascia, 
platysma  myoides  muscle,  and  superficial  layer  of  the  deep  fascia,  and  is  crossed  by 
tlie  liypo-glossal  nerve,  lingual  vein,  and  digastric  and  stylo-hyoid  mu.scles.  This 
jiortion  of  the  vessel  rests  upon  the  middle  constrictor  muscle  of  the  pharynx  and 
the  superior  larj'ngeal  nerve. 

The  second  portion  runs  along  the  upper  l)order  of  the  hyoid  bone  beneath  the 
hyo-glossus  nuiscle,  lingual  vein,  hypo-glossal  nerve,  diga.stric  and  stylo-hyoid 
muscles,  submaxillary  gland,  superficial  layer  of  the  deep  fa.scia,  platysma  myoides 
muscle,  and  superficial  fascia  and  skin. 

It  rests  here  upon  the  middle  constrictor  muscles  of  the  pharynx  and  the 
genio-hyo-glossus  muscle.  This  portion  is  the  point  of  election  in  ligation  of  the 
artery. 

The  third  portion  ascends  between  tlie  hyo-glossus  and  genio-hyo-glossus 
muscles,  pierces  the  latter  muscle,  and  runs  between  it  and  the  lingualis  muscle  in 
the  under  surface  of  the  tongue  as  far  as  the  tip  of  that  organ. 

To  ligature  the  lingual  artery  in  its  second  jiortion,  or  point  of  election,  the 
patient  should  be  placed  in  the  same  position  as  for  ligature  of  the  common  and 
external  carotid  arteries,  and  the  lower  jaw  drawn  upward.  The  incision  extends 
from  the  anterior  border  of  the  sterno-mastoid  muscle  forward  along  the  upper 
border  of  the  greater  cornu  of  the  hyoid  bone.  The  skin,  superficial  fascia, 
platysma  myoides  muscle,  branches  of  the  facial  and  anterior  jugular  veins,  and 
the  superficial  layer  of  the  deep  fascia  are  divided.  The  submaxillary  gland 
is  displaced  and  held  well  upward  on  the  lower  jaw,  and  the  process  of  deep 
fa.scia  beneath  the  gland  divided.  The  tendon  and  bellies  of  the  diga.stric  muscle, 
the  stylo-hyoid  muscle,  the  hypo-glo.s.sal  nerve,  the  lingual  vein  (which  is  just 
below  the  nerve),  the  injdo-hyoid  and  the  hyo-glossus  muscle,  will  be  exposed. 
The  stylo-hyoid  muscle  and  the  tendon  of  the  digastric  muscle  are  drawn  down- 
ward, the  lingual  vein  and  hj-po-glossal  nerve  upward,  and  an  incLsion  one-half 
of  an  inch  long  should  be  carefully  made  through  the  hyo-glo.ssus  muscle  just 
al)ove  the  hyoid  Ixme.  If  the  incision  through  the  hyo-glos.sus  mu.scle  is  accurately 
made,  the  artery  will  project  into  the  wound.  The  aneurvsm  needle  is  passed 
around  the  artery,  and  may  include  the  vena;  comites.  The  submaxillar}'  gland 
should  not  be  injured,  as  this  accident  would  probably  give  rise  to  a  salivary 
fistula.     To    avoid  the  danger  of  opening  the  pharynx  when  incising   the   hj'o- 


190    .  SURGICAL  ANATOMY. 

glossus  muscle  care  is  required.  Instead  of  dividing  tlie  hyo-glossus  muscle,  the 
artery  may  be  ligatured  immediately  before  it  passes  under  the  outer  border  of  tliat 
muscle. 

The  first  jwrtion  of  the  lingual  artery  is  reached  through  an  incision  one  inch 
long,  carried  from  the  sterno-mastoid  muscle  forward  along  tlie  upper  border 
of  the  greater  cornu  of  the  hyoid  bone.  The  position  of  the  patient  should  be  the 
same  as  that  for  the  foregoing  operation.  Skin,  superficial  fascia,  platysma  myoides 
nuiscle,  and  sui^erficial  layer  of  the  deep  fascia  are  divided.  The  .submaxillary 
gland  is  displaced  upward,  and  the  process  of  deep  fascia  beneath  the  gland  divided. 
The  lingual  vein  and  hypo-glo.ssal  nerve  are  exposed  and  drawn  upward,  and  the 
artery  secured  as  it  passes  under  the  posterior  margin  of  the  hyo-glo.ssus  muscle. 
This  operation  is  more  difficult  than  ligature  of  the  .second  portion  of  the  vessel ; 
tliis  is  due  to  the  fiiet  that  the  lingual  vein,  hypo-glossal  nerve,  .stylo-hyoid 
muscle,  and  posterior  belly  of  the  diga.stric  mu.scle  lie  in  front  of  the  artery.  This 
portion  of  the  artery  may  be  secured  at  its  origin  through  an  incision  two  inches 
long,  made  along  the  anterior  border  of  the  sterno-mastoid  muscle.  The  center  of 
the  incision  .should  be  opposite  the  greater  cornu  of  the  hyoid  bone.  The  location 
of  the  external  carotid  ai'tery  is  ascertained,  as  described  under  ligatui-e  of  that 
vessel,  and  the  origin  of  the  lingual  artery  located  opposite  the  greater  cornu  of  the 
hyoid  bone.     The  hypo-glossal  nerve  and  lingual  and  facial  veins  must  be  avoided. 

Irregularities. — The  most  common  irregularities  of  the  lingual  artery  are 
the  following :  It  may  arise  from  a  trunk  common  to  it  and  the  facial  artery,  or 
from  a  trunk  common  to  the  superior  tliyroid,  Hngual,  and  facial  arteries.  It  may 
pierce  the  hyo-glossus  muscle.  Occasionally  it  is  given  off  as  a  branch  of  tlie 
fVicial  or  internal  maxillary  artery.  Its  sublingual  branch  may  arise  from  the 
facial  artery,  and  the  hyoid  branch  may  be  absent. 

The  facial  artery  may  be  secured  at  its  origin  or  as  it  passes  over  the  lower 
border  of  the  lower  jaw  at  the  anterior  inferior  angle  of  the  masseter  muscle.  To 
ligature  the  facial  artery  at  its  origin,  wliich  is  just  above  tliat  of  the  lingual  artery, 
an  incision  should  be  made  similar  to  that  for  ligation  of  the  external  carotid  artery, 
except  that  the  center  of  the  incision  should  be  just  above  the  gi'eater  cornu  of  the 
hyoid  bone.  The  facial  and  lingual  veins,  anterior  division  of  the  temporo- 
maxillary  vein,  and  hypo-glossal  nerve  should  be  avoided.  To  tie  the  artery  as 
it  turns  over  the  lower  border  of  the  lower  jaw,  an  incision  one  incli  long  should 
be  made  below  and  parallel  with  tiiis  l>order  of  the  jaw,  so  that  the  resulting  scar 
will  not  bo  ]ironiiii(iit.  The  skin,  superficial  fascia,  platysma  myoides  muscle, 
and  superlicial  layer  of  the  deep  fascia  arc  diviili-d.  As  tlie  facial  vein  is  behind 
the  artery,  the  needle  should  be  passed  from  l)eliind  forward. 

Irregularity. — The  irregularity  of  the  facial  artery  wliich  is  of  importance 


PLATE  XLII. 


Occipital  a.       SternoiTiastoid  m. 


Superficial  fascia 
Deep  fascia' 
Splenius  capitis  m 


Venae  comites 


Splenius  capitis  m. 


Princeps  cervicis  a. 
Sterno-mastoid  m 


EXPOSURE  OF  OCCIPITAL  ARTERY  FOR  LIGATION. 
1U2 


PLATE 


Temporal  a. 
Temporal  v. 


Auriculo-temporal  n. 
Superficial  fascia 


EXPOSURE  OF  AURICULO-TEMPORAL  NERVE  AND  TEMPORAL  ARTERY. 
S-    n-13  193 


4 


LIGATION  OF  ARTERIES  OF  HEAD  AND  NECK.  !<):> 

is  tlio  following :  It  may  teniiinate  as  the  sul)niental  artvrv,  its  area  of  distri- 
Itution  in  the  face  being  siipiiliiMl  hy  the  nasal  hraneh  of  the  ophthalmic,  the 
transverse  facial,  or  the  internal  maxillary  artt-ry. 

The  occipital  artery  is  ligatured  for  cirsoid  aneurysm.  It  may  be  tied  at  its 
origin,  or  as  it  passes  through  the  occipital  region.  To  tie  it  at  its  origin  the 
shoulders  should  be  elevated,  the  neck  well  extended,  and  an  incision  made  along 
the  upper  part  of  the  anterior  border  of  the  sterno-mastoid  muscle.  The  origin  of 
the  arter}'  will  be  found  by  tracing  backward  over  the  external  carotid  arteiy  the 
hypo-glossal  nerve,  which  winds  I'nim  bt'hind  forward  over  that  jiortioii  of  the 
vessel.  In  the  occipital  region  the  artery  may  be  secured  through  an  incision 
carried  oblicjuely  backward  and  slightly  upward  from  the  tip  of  the  mastoid 
process.  The  structures  divided  in  the  occipital  region  are  the  skin,  superficial 
fascia,  superficial  nerves  and  vessels,  superficial  layer  of  the  deep  fascia,  a  portion 
of  the  sterno-mastoid  muscle,  posterior  process  of  the  deep  fascia  (prevertebral 
fascia),  and  the  splenius  capitis  muscle.  The  artery  may  be  readily  found  in  this 
region,  at  a  point  midway  between  the  mastoid  process  and  the  external  occipital 
protuberance. 

Irregularities. — The  irregularities  of  the  occipital  artery  which  are  of  im- 
portance are  the  following  :  It  may  arise  from  the  internal  carotid  artery  or  the 
ascending  cervical  branch  of  the  inferior  thyroid  artery  ;  it  may  cross  over,  instead 
of  under,  tlie  upper  portion  of  the  sterno-mastoid  muscle  ;  it  may  give  origin  to 
the  posterior  auricular  or  ascending  pharyngeal  artery. 

Irregularities  of  the  ascending  pharj-ngeal,  posterior  auricular,  superficial 
temporal,  and  internal  maxillary  arteries  are  not  of  much  surgical  imj^ortance. 

The  superficial  temporal  artery,  like  the  occipital,  is  ligatured  in  injuries  and 
cirsoid  aneurysm.  The  artery  usually  Ijifurcates  into  the  anterior  and  posterior 
temporal  one  and  one-half  to  two  inches  above  the  zygoma,  but  it  frequently 
divides  at  a  lower  level.  The  artery  may  be  felt  pulsating  just  in  front  of  the 
]iinna  of  the  ear,  where  it  crosses  the  posterior  root  of  the  zvgoma ;  this  is  the 
point  at  which  it  should  be  tied.  The  incision  should  be  vertical,  about  one  inch 
in  k'ngth,  and  be  made  over  the  vessel  in  front  of  the  pinna.  The  .structures 
ilivided  are  the  skin,  superficial  fascia,  and  deep  fascia.  The  superficial  temporal 
vein  lies  behind  the  artery  and  overlaps  it,  and  the  auriculo-temporal  nen'e 
emerges  from  beneath  the  artery  and  vein,  and  then  runs  behind  the  vein.  The 
temporal  branches  of  the  facial  nerve  cross  the  artery  and  vein  in  the  jjarotid 
gland.     The  needle  should  be  passed  from  behind  forward. 

The  internal  carotid  artery  is  rarely  ligatured,  Init  may  be  tied  after  injury 
of  the  vessel  and  for  traumatic  aneurysm.  The  line  for  this  vessel  is  the  same  as 
that  for  the  common  carotid  artery.     Its  only  accessible  and  superficial  portion 


196  .  SURGICAL  ANATOMY. 

is  at  its  origin,  and  is  about  one  inch  in  length.  The  internal  carotid  artery  begins 
at  the  bifurcation  of  the  common  carotid  artery,  which  is  opposite  the  upper  bor- 
der of  the  tiiyroid  cartilage.  At  first  it  lies  external  to  and  on  the  same  plane  as 
tlie  external  carotid  artery,  but  it  gradually  passes  beneath  the  latter  vessel.  In 
front  of  it  in  this  location  are  the  skin,  superficial  fascia,  platysraa  myoides  mus- 
cle, superficial  layer  of  the  deep  fascia,  anterior  border  of  the  sterno-mastoid 
muscle,  and  the  wall  of  the  carotid  sheath  ;  behind  it  are  the  pneumogastric  nerve, 
prevertebral  fascia,  superior  sympathetic  ganglion,  and  rectus  capitis  anticus  major 
muscle  ;  to  the  outer  side  are  the  pneumogastric  nerve  and  internal  jugular  vein  ; 
and  to  the  inner  side  are  the  external  carotid  artery,  ascending  pharj-ngeal  artery, 
and  pharynx.  The  patient  should  be  placed  in  the  same  position  as  for  liga- 
ture of  the  common  carotid  artery.  An  incision  three  inches  long  is  made 
over  the  anterior  border  of  the  sterno-mastoid  muscle,  the  center  of  the  incision 
being  slightly  above  the  level  of  the  upper  border  of  the  thyroid  cartilage.  Skin, 
sui^erficial  fascia,  platysma  myoides  mu.scle,  and  superficial  layer  of  the  deep 
fascia  are  divided.  The  sterno-mastoid  muscle  is  drawn  outward,  the  posterior 
belly  of  the  digastric  muscle  upward,  the  external  carotid  artery  inward,  and 
the  internal  carotid  artery  outward.  The  anterior  wall  of  the  sheath  of  the  artery 
should  be  carefully  opened,  and  the  needle  passed  from  witliout  inward,  away 
from  the  internal  jugular  vein  and  pneumogastric  nerve.  In  many  cases  the  facial 
and  lingual  veins  cross  the  internal  carotid  artery  to  empty  into  the  internal 
jugular  vein. 

Collateral  Circulation. — The  i'ollateral  circulation  is  established  by  the 
anastomosis  of  the  vertebral  arteries  and  opposite  internal  carotid  with  the  liga- 
tured artery  through  the  circle  of  Willis. 

Irregularities. — The  irregularities  of  the  internal  caroti<l  artery  which  are 
of  importance  are  the  following :  It  may  ari.se  from  the  arch  of  the  aorta  or  the 
innominate  artery  ;  its  cervical  portion  may  be  tortuous ;  it  may  give  origin  to  the 
occipital  artery. 


OPERATIONS  UPON  NERVES  OF  HEAD  AND  NECK. 

The  supra-orbital  nerve  is  exposed  at  the  supra-orbital  notch  or  foramen, 
which  is  located  at  the  junction  of  the  middle  one-third  with  the  inner  one-third 
of  the  supra-orl)ital  margin.  The  eyelid  is  drawn  downward  and  the  eyebrow 
held  steady  wliilc  a  tr:ms\-erso  incision  is  made  along  the  sujira-orbital  margin. 
The  incision  is  one-half  to  three-fourths  of  an  inch  in  Icngtli  and  divides  skin, 
supci'ficial     fascia,    and     (M'bicularis    palpebrarum     muscle.      The    nerve    is    now 


PLATE  XLIV, 


Orbicularis  palpebrarum  m 
Periosteum 
Superficial  fascia 


1  > 


EXPOSURE  OF  SUPRAORBITAL  ARTERY  AND  NERVE. 
197 


OPERATIONS  UPON  NERVES  OF  HEAD  AND  NECK.  V.)'.) 

exposed,  the  supra-tn-hital  vessels  beiiij;-  on  its  outer  side.  Tiir  palpebral  faseia 
is  divided,  the  orhilal  fal  dcpri'sscd,  ami  the  nerve  traced  into  tln^  orhii  as  far  us 
possible,  so  that  the  i'ronhd  nerve  may  be  reached  and  divided  just  bei'orc  it  bil'ur- 
eates  into  the  supra-orbital  and  supra-trochlcar  nerves.  About  an  inch  of  the 
.-:u{ira -orbital  nerve  is  resected.  The  supra-orbital  vessels  may  be  injured.  The 
supra-iirliital  arlciy  may  be  liii-ated  through  the  same  incision.  • 

The  infra-orbital  nerve  may  be  resected  thriiui;h  an  incisitm  three-fourths  of 
an  inch  long,  made  about  one-fourth  to  three-eighths  of  an  inch  below,  and  paralkd 
with,  the  infra-orbital  margin,  so  that  its  center  will  lie  over  the  infra-orbital 
foramen,  which  is  situated  in  a  line  drawn  from  the  supra-orbital  notch  to  the 
second  bicuspid  tooth  of  the  upper  jaw,  and  between  one-fourth  and  three-eighths 
of  an  ini'h  below  the  infra-orbital  margin.  The  skin,  superficial  fascia,  orbicularis 
jialpebrarum  muscle,  and  levator  labii  superioris  mu.scle  are  divided,  the  nerve  is 
drawn  out  of  the  foramen,  and  as  much  as  possible  resected. 

The  superior  maxillary  nerve  is  resected  in  the  si)heno-maxillary  fossa  by 
way  of  the  antrum  of  Highmore,  or  through  an  incision  at  the  side  of  the  face. 
These  operations  are  described  in  volume  i,  page  503. 

The  Gasserian  ganglion  is  removed  through  an  o.steo-plastic  resection  of  the 
temporal  region,  or  by  way  of  the  ptery go-maxillary  region.    (See  Vol.  i,  page  595.) 

The  inferior  maxillary  nerve  is  exposed  at  its  exit  from  the  foramen  ovale. 
The  retlected  flap  is  scjuare,  its  attached  margin  being  below.  Two  vertical 
incisions  are  made,  parallel  with  the  margins  of  the  ramus  of  the  lower  jaw,  and 
extend  from  the  level  of  the  upper  margin  of  the  zygoma  to  half  way  down  the 
ramus  ;  the  upper  extremities  of  the  incisions  are  connected  by  a  transverse  incision. 
The  skin  and  superficial  fascia  are  divided,  the  zygoma  is  sawed  at  each  end,  the 
temporal  fascia  and  the  masseteric  fascia  are  divided,  the  zygoma  and  the  mas- . 
seter  muscle  are  displaced  downward,  and  the  masseteric  vessels  and  nerve  are 
severed.  Care  is  rec^uired  to  avoid  injuring  Stenson's  duct  and  some  of  the  large 
branches  of  the  facial  nerve  which  are  at  the  attached  margin  of  the  flap.  The 
coronoid  process  of  the  lower  jaw  is  divided  and  reflected  n|iward  with  the 
temporal  muscle  ;  and  the  upper  head  of  the  external  pterygoid  nnisdc  is  sepa- 
rated from  the  pteiygoid  ridge  of  the  sphenoid  bone  and  displaced  downward. 
The  nerve  can  then  be  exposed  at  the  foramen  ovale  and  divided  with  scissors. 
The  small  meningeal  artery  is  nece.ssarily  divided  with  the  nerve.  The  foramen 
ovale  is  situated  about  one-fourth  of  an  inch  in  front  of  the  spine  of  the  .sphenoid 
bone,  just  l)ehind  the  base  of  the  external  pterygoid  i)late,  and  in  a  transverse  line 
passing  tln-ough  the  emincntia  articularis  of  the  temporal  bone.  This  operation 
is  hardly  justifiable  on  account  of  the  number  of  important  tissues  injured,  the 
resulting  paralysis  of  the  muscles  of  mastication  and  of  the  mylo-hyoid  muscle 


200  SURGICAL  ANATOMY. 

and  anterior  belly  of  the  digastric  mnsclc,  tlie  partial  loss  of  power  in  movinji;  the 
lower  jaw,  and  the  dangers  of  infection  and  sni)pnration  in  so  inaccessible  a 
region  as  the  ptervgo-niaxillary  space. 

The  inferior  dental  nerve  may  be  resected  at  the  mental  foramen,  in  the 
inferior  dental  canal,  or  before  it  enters  that  canal.  It  is  preferably  resected 
before  it  enters  the  inferior  dental  canal,  in  (H'der  that  all  the  dental  and  gingival 
fibers  of  the  nerve  can  be  included.  This  portion  of  the  nerve  can  be  reached  by 
an  incision  through  the  cheek  or  through  tlie  mucous  membrane  of  the  mouth. 
The  external  incision  is  preferable  because  a.sepsis  is  an  impossibility  in  wounds  of 
the  mouth,  the  external  method  is  more  easily  performed,  and  the  incision  can  be 
so  located  that  the  .scar  will  not  be  prominent.  The  incision  in  the  external 
method  is  angular  and  made  along  the  posterior  hurder  of  the  ramus  to  the  angle 
of  the  lower  jaw,  and  thence  forward  along  the  lower  border  of  the  lower  jaw,  each 
limb  of  the  incision  being  about  one  inch  in  length.  Only  the  skin  and  super- 
ficial fascia  are  divided  in  the  first  stage  of  the  operation.  Next  divide  the  mas- 
.seteric  fascia  and  the  platysma  myoides  muscle,  exercising  care  to  avoid  injuring 
the  buccal  and  supra-maxillary  branches  of  the  facial  nerve  and  the  parotid  gland. 
The  lower  limb  of  the  incision  should  not  extend  far  enough  forward  to  divide  the 
facial  artery  or  vein.  The  lower  portion  of  the  masseter  muscle  is  separated  from 
the  ramus  of  the  lower  jaw  with  the  periosteal  elevator  and  the  knife,  and  displaced 
upward.  A  small  trephine  is  applied  to  the  ramus  midway  between  its  anterior 
and  posterior  borders,  and  just  above  the  level  of  the  alveolar  margin  of  the  lower 
jaw.  The  trephine  first  divides  the  upper  and  thinner  portion  of  the  circle  of 
bone  ;  the  remainder  of  the  incision  thrDugli  tiie  bone  must  be  completed  witli  the 
chisel  and  elevator,  so  that  the  inferior  dental  vessels  will  not  lie  injured.  The 
inferior  dental  vessels  and  nerve  are  detected  lying  upon  the  internal  lateral 
ligament  of  the  lower  jaw.  The  nerve  is  separated  from  the  vessels,  drawn  out 
with  a  blunt  hook,  and  as  much  of  it  as  possible  resected. 

In  neurectomy  of  the  inferior  dental  nerve  thrLiugli  the  mouth,  the  upper  teeth 
are  widely  separated  from  tlie  lower  with  a  gag,  and  a  vertical  incision  about  an 
incli  long  is  maile  through  the  mucous  membrane  along  the  inner  margin  of  the 
anterior  border  of  the  ramus  of  the  lower  jaw.  Tlie  anterior  margin  of  the  ramus 
is  exposed,  and  the  mucous  membrane  is  separated  from  the  ramus  with  a  small 
periosteal  elevator.  The  lingual  nerve  is  seen,  the  separation  is  extended  a  short 
distance  rurthcr  liackward,  and  the  s])ine  of  lione  (spine  of  Spix)  just  below  tlie 
iiil'cri(ir  dental  foramen  is  located  with  tlie  finger.  Tliis  spine  gives  attachment  to 
tlie  internal  lateral  ligament  of  tlie  lower  jaw;  this  ligament  hides  from  view  the 
inferior  dental  vessels  and  nerve  which  lie  between  it  and  the  ramus  of  the  lower 
jaw.     The  internal  lateral  ligament  is  cautiously  divided  with  long,  slender  scis- 


PLATE  XLV, 


Mucous  membrane 
Lingual  n. 


EXPOSURE  OF  LINGUAL  NERVE, 
202 


PLATE  XLVI. 


Posterior  auricular  n. 
Posterior  auricular  a. 
Facial  n. 

Deep  fascia 

Superficial  fascia 


* 

V 


^ 


Mastoid  process 

Sterno-mastoid  m 


Posterior  belly  of  digastric  m. 


EXPOSURE  OF  FACIAL  NERVE. 
203 


OPERATIONS   UPON  NERVES  OF  HEAD   AND  NECK.  205 

sors,  ami  tlic  iiil'riior  ilcntal  vessels  ami  iutvo  are  exposcMl  at  tlicir  entrance  into 
the  interii)r  ilrnlal  canal.  The  ncrvo  and  vessels  are  gently  drawn  lorwanl  witli  u 
small  blunt  hook  and  traced  upward  for  about  a  half  inch  above  their  point  of 
entrance  into  the  inferior  dental  canal.  Here  the  nerve  and  vessels  are  not  in  so 
close  contact  and  can  be  separated.  The  nerve  is  i.solated  from  the  vessels,  and 
about  one-l'ourth  or  one-half  of  an  inch  removed,  the  upper  end  of  the  segment 
being  divided  tirst  because  of  the  fact  that  the  upper  part  of  the  nerve  retracts 
after  being  divided.  If  the  nerve  and  vessels  are  traced  too  high,  the  internal 
maxillary  artery  is  endangered.     The  wound  in  the  mucous  membrane  is  not  closed. 

The  lingual  (gustatory)  nerve  is  divided  or  a  portion  of  it  excised  for  pain- 
ful conditions  of  the  tongue,  as  advanced  cancer  of  that  organ.  The  nerve  may 
be  expo.sed  by  merely  cutting  through  the  mucous  membrane  of  the  floor  of  the 
mouth  near  the  side  of  the  tongue,  and  opposite  the  second  molar  tooth.  The 
nerve  may  also  be  exposed  by  dividing  the  mucous  membrane  about  one-half  of  an 
inch  below  and  behind  the  last  molar  tooth,  where  the  nerve  can  readily  be  felt. 

The  auriculo-temporal  nerve  is  exposed  where  it  first  lies  in  relation  with  the 
superficial  temporal  vessels  over  the  posterior  root  of  the  zygoma  and  in  front  of 
the  pinna  of  the  ear.  The  incision  is  the  same  as  that  made  for  ligation  of  the 
superficial  temporal  artery.  The  nerve  is  found  just  to  the  outer  side  of  the  super- 
ficial temporal  vessels. 

The  facial  nerve  is  stretched  for  twitching  of  the  muscles  of  expression,  asso- 
ciated with  more  or  less  pain  (tic  convulsif).  The  nerve  is  secured  near  the  stylo- 
mastoid foramen,  as  it  lies  superficial  to  the  styloid  process  and  above  the 
posterior  belly  of  the  digastric  muscle. 

In  this  location  tlie  trunk  of  the  nerve  is  found  before  it  gives  off  the  stylo- 
hyoid and  digastric  branches,  and  before  it  bifurcates  into  its  two  divisions.  The 
posterior  auricular  nerve  arises  from  it  close  to  the  stylo-mastoid  foramen.  The 
incision  begins  behind  the  pinna  of  the  ear,  opposite  the  external  auditory  meatus, 
and  is  carried  Ijcliind  the  lobule  of  the  ear  downward  and  forward  to  the  angle  of 
the  lower  jaw.  A  transverse  incision  may  also  be  made  behind  the  lobule.  The 
skin,  superficial  fascia,  superficial  layer  of  the  deep  fi^scia,  and  branches  of  the 
auricularis  magnus  nerve  are  divided.  The  flaps  which  have  been  made  are  now 
dissected  from  the  j^arotid  gland,  sterno-mastoid  muscle,  and  mastoid  process,  the 
posterior  auricular  nerve,  vein,  and  artery  being  avoided.  The  parotid  gland  is 
separated  from  the  mastoid  process,  and  the  trunk  of  the  nerve  is  found  above  the 
posterior  belly  of  the  digastric  muscle,  lying  upon  the  styloid  process.  The  nerve 
is  stretched  by  lifting  it  with  a  blunt  hook. 

The  spinal  accessory  nerve  is  stretched  or  divided  for  spasmodic  wryneck. 
Division  or  excision  of  a  j)ortion  of  the  nerve  offers  better  results.     The  nerve  is 


206  SURGICAL  ANATOMY. 

secured  at  the  anterior  or  at  the  posterior  border  of  the  sterno-mastoid  muscle. 
When  it  is  exposed  behind  tlie  sterno-mastoid  muscle,  it  should  he  traced 
upward  and  divided  above  its  sterno-mastoid  branches.  In  its  course  downward 
from  the  jugular  foramen  the  nerve  runs  beneath  the  internal  jugular  vein, 
the  occipital  artery  and  posterior  belly  of  the  digastric  muscle,  and  enters  the  under 
surface  of  the  sterno-mastoid  muscle  abnut  midway  between  its  two  borders  and 
about  two  inches  from  the  tip  of  the  mastoid  process.  It  emerges  from  the  muscle 
at  about  the  middle  of  its  posterior  liorder.  Between  the  posterior  belly  of 
the  digastric  muscle  and  the  point  where  it  enters  the  sterno-mastoid  muscle 
it  is  accompanied  by  the  superior  sterno-mastoid  artery. 

Before  exposing  the  nerve  at  the  anterior  border  of  the  sterno-mastoid 
muscle  the  patient  is  placed  on  his  back,  with  the  shoulders  raised  and  the  neck 
extended.  Tlie  incision  begins  at  the  anterior  border  of  the  mastoid  process,  and 
is  carried  downward  for  two  and  one-half  or  three  inches  along  the  anterior  margin 
of  the  sterno-mastoid  muscle.  The  skin,  suj^erficial  fascia,  platysma  myoides 
muscle,  a  branch  of  the  auricularis  magnus  nerve,  and  the  deep  ftiscia  are  divided, 
the  external  jugular  vein  being  avoided.  The  sterno-mastoid  muscle  is  drawn 
outM'ard,  and  the  nerve,  with  its  accompanying  sterno-mastoid  artery,  can  be  felt 
just  below  the  prominent  transverse  process  of  the  atlas,  lying  upon  the  levator 
anguli  scapulae  muscle. 

Before  exposing  the  spinal  accessory  nerve  at  the  posterior  border  of  the 
sterno-mastoid  muscle  the  shoulders  are  elevated,  the  face  is  turned  to  the  opposite 
side,  and  the  neck  is  flexed  laterally  toward  the  opposite  shoulder.  The  incision 
is  made  along  the  posterior  border  of  the  sterno-mastoid  muscle,  is  two  inches  in 
length,  and  its  center  is  at  the  middle  of  that  border  of  the  muscle.  The  skin, 
superficial  fascia,  platysma  myoides  muscle,  and  the  superficial  layer  of  the  deep 
fascia  are  divided.  The  small  occipital  nerve  is  easily  found  as  it  runs  along  the 
upper  one-half  of  the  posterior  border  of  the  sterno-mastoid  muscle.  This  nerve  is 
traced  downward  to  the  spinal  accessory  nerve,  with  which  it  forms  a  loop.  The 
spinal  acces.sory  nerve  is  then  traced  beneath  or  through  the  deeper  jiortion  of  the 
sterno-mastoid  muscle  and  divided. 

The  superficial  branches  of  the  cervical  plexus  may  be  exposed  through  the 
same  incision  as  that  made  at  the  posterior  border  of  the  sterno-mastoid  muscle  for 
the  spinal  accessory  nerve.  The  auricularis  magnus  nerve  runs  from  the  middle 
of  the  posterior  border  of  the  sterno-mastoid  muscle  toward  the  j^iima.  Tlie 
occipitalis  minor  nerve  lies  between  the  superficial  layer  of  the  deep  fascia  and 
its  posterior  process  (prevertebral  fascia),  and  just  behind  tlic  u|iper  one-half  of 
the  posterior  margin  of  the  sterno-mastoid  muscle.  The  superficial  cervical  nerve 
emerges    from    under  the  sterno-mastoid    muscle    at  the    middle    of  its  posterior 


PLATE  XLVIl 


Stemo-mastoid  m. 
Superficial  layer  of  deep  fascia 
Platysma  myoides  m. 
Superficial  fascia 
Descending  branches  of  cervical  plexus  (n.) 


Prevertebral  fascia 

Scalenus  anticus  m. 

Transversalis  colli  a. 


Platysma  myoides 
External  jugular  v 


Scalenus  medius  m.- 


;? 


Posterior  jugular  v 

Posterior  belly  omohyoid  m 

Upper  trunk  of  brachial  plexus 
Middle  trunk  of  brachial  plexus 
Lower  trunk  of  brachial  plexus 

Subclavian  a 


EXPOSURE  OF  BRACHIAL  PLEXUS  OF  NERVES. 
208 


I 


THE  MOUTH.  209 

honlcr,  turns  dowiiwnnl  al<inij;  tliat  iiiart;in  for  a  sliort  distance,  and  thou  runs 
transversely  forward.  Tlio  dencnnliN;/  xitpcrjlc'Ktl  Imuich  nf  the  (rrvieal  plc.r>is,  which 
divides  into  the  supra-sternal,  supra-tdavicular,  and  supra-acroniial  nerves,  is 
found  running  along  the  posterior  border  of  the  sterno-mastoid  muscle  just  below 
the  middle  of  that  margin,  and  usually  passes  between  the  sterno-mastoid  muscle 
and  the  external  jugular  vein. 

TIk'  brachial  plexus  may  be  stretched  in  the  neck  external  to  the  scalenus 
anticus  muscle.  It  onerges  from  between  the  scalenus  anticus  and  scalenus 
medius  muscles,  and  converges  toward  the  apex  of  the  axilla.  The  patient 
is  placed  on  the  back,  with  the  shoulders  elevated,  the  neck  extended,  and 
the  fiico  turned  to  the  opposite  side.  The  incision  begins  al)out  one-half  of 
an  inch  above  the  middle  of  the  clavicle.  It  is  carried  directly  upward 
ibr  about  three  inches,  and  parallel  with  the  posterior  margin  of  the  sterno- 
mastoid  muscle.  The  skin,  superficial  fascia,  and  platy.sma  myoides  muscle 
are  divided.  The  external  jugular  vein,  which  lies  to  the  inner  side  of  the 
incision,  should  be  located,  and  it  may  be  nccessaiy  to  divide  the  posterior 
external  jugular  or  transverse  cervical  and  supra-scapular  veins  between  ligatures. 
The  superficial  layer  of  the  deep  fascia  is  next  divided.  The  posterior  belly 
of  the  omo-hyoid  muscle  is  drawn  upward,  the  transversalis  colli  artery  and  the 
cords  of  the  jilexus  and  the  position  of  the  outer  border  of  the  scalenus  anticus 
muscle  are  located  with  the  finger.  The  posterior  process  of  the  deep  fascia  (pre- 
vertebral fascia)  is  divided  a  short  distance  external  to  the  scalenus  anticus 
muscle,  avoiding  the  nerve  to  the  subclavius  muscle,  which  runs  along  the 
outer  border  of  the  scalenus  anticus  muscle,  and  the  transversalis  colli  arterj', 
which  runs  across  the  upper  part  of  the  jilexus.  The  prevertebral  fascia  is 
reflected  outward.  The  upper  and  miildle  cervical  trunks  of  the  plexus  are 
found  above  the  subclavian  artery,  whereas  the  lower  trunk  is  overlapped  by  the 
upper  margin  of  that  artery. 


THE  MOUTH. 

The  student  should  now  examine  the  mouth,  the  pharynx,  the  larynx,  and 
the  nose.  These  are  attached  to  the  anterior  portion  of  the  skull  which  has  been 
divided  previous  to  the  dissection  of  the  prevertebral  muscles. 

The  mouth  is  situated  at  the  commencement  of  the  alimentarv  canal.  It 
contains  the  organs  of  mastication,  those  of  the  sense  of  taste,  some  of  the  organs 
of  speech,  and  it  acts  as  a  resonating  cavity.  The  buccal  cavity  (cavity  of  the 
S—  11-14 


210  SURGICAL  ANATOMY. 

mouth)  is  divided  into  two  parts  liy  the  teeth  and  alveolar  processes — viz.,  the  ves- 
tibule and  the  mouth  jaroper. 

The  Vestibule  is  situated  between  the  lips  and  cheeks  externally,  and  the 
teeth  and  gums  internally.  The  walls  of  the  vestibule,  except  when  it  is  dis- 
tended, are  in  contact.  In  front  it  opens  upon  tlie  face  at  the  l>uccal  orifice,  and 
beiiind  the  last  molar  teeth  it  conununicatesi  with  the  mouth  jtroper,  even  when 
the  teeth  are  in  contact,  so  that  in  tetanus  or  during  treatment  of  fractures  of  the 
lower  jaw  a  patient  may  be  fed  liquids  througli  a  tube  passed  from  the  back  part 
of  the  vestibule  into  the  mouth  proj^er.  Under  these  circumstances  a  preferable 
method  of  feeding  may  be  through  a  catheter  introduced  through  the  nose. 

The  Lips  are  composed  of  the  skin,  superficial  fascia,  orbicularis  oris  muscle 
and  the  muscles  inserted  around  it,  areolar  tissue,  and  mucous  membrane.  The 
first  three  laj^ers  of  the  lips — skin,  superficial  fascia,  and  muscular  tissue — have 
been  described  -with  the  face.  The  margins  of  the  lips  are  covered  with  dry, 
red  mucous  membrane,  which  is  continuous  with  the  skin,  and  contains  numerous 
vascular  i^ajjill*  and  touch  corpuscles.  Internalh'',  the  mucous  membrane  is 
retlected  from  the  upper  and  lower  lips  upon  the  gums,  and  in  the  median  line 
forms  two  filds — the  frtcnum  labii  superioris  and  frtenum  laljii  inferioris.  Along 
the  line  of  junction  of  the  skin  and  mucous  membrane  "fever  blister,"  or  herpes 
labialis,  is  very  common.  Through  cicatricial  contraction  after  burns  of  the  lips 
and  cheeks  the  buccal  orifice  may  be  much  distorted.  The  deformity  can  be 
lessened,  if  not  corrected,  by  plastic  operation.  The  areolar  tissue,  or  submucous 
layer,  contains  the  coronary  vessels,  branches  of  the  infra-orbital  and  mental 
nerves,  and  the  labial  glands.  The  coronary  vessels  completelj'  encircle  the 
buccal  orifice  near  the  free  margin  of  the  li}>s,  lying  immediatelj'  sujjerficial  to 
the  mucous  membrane  in  the  submucous  layer. 

The  labial  glands  are  situated  around  the  orifice  of  the  mouth,  in  the  sub- 
nnicous  layer  of  the  lips.  The_y  are  small  lobulated  bodies,  about  the  size  of  a 
small  pea,  and  their  ducts  open  into  the  mouth.  They  secrete  a  mucous  fluid. 
When  the  ducts  of  these  glands  become  occluded,  mucous  retention  cysts  develop. 

Between  the  lips  is  the  buccal  orifice,  which  extends  between  the  angles  of 
the  mouth. 

In  harelip  operations  and  after  excision  of  a  large  segment  of  the  lip  in 
removing  an  epithelioma,  the  mobility  and  elasticity  of  the  lips,  particularly  of 
the  lower  liji,  allow  approximation  of  the  edges  of  the  wound. 

The  lymphatics  fi-om  the  median  imrtinn  of  (be  lower  lip  pass  to  a  lymphatic 
gland  situated  just  above  the  body  of  the  hyoid  bone  ;  those  from  the  lateral  ]wr- 
tions  pass  to  the  submaxillary  lyni|i]iatic  glands,  into  which  the  lymjihatics  of  the 
U]i]>er  lip  also  empty. 


PLATE 


Superior  m 


Superior  tu 
Mio'JIe  tur 


Hyoid  bone 

Mylo-hyoid 

Thyro- 
edge 

Ventricle  of 
Thyroid  cart 


aphra^ma  sellae 
vum  sellae 

Spenoidal  cell 


Middle  meatus 


Naso-pharynx 

Orifice  of  Eustachian  tube 

Hard  palate 
Soft  palate 

Uvula 

Anterior  pillar  of  fauces 
-Tonsil  in  recess  of  fauces 
Oro-pharynx 

Epiglottis  (cut  edge) 
Aryteno-epiglottidean  fold    '. 


t 


Latyngo-pharynx 
uprarimal  portion  of  larynx 
False  vocal  cord 
True  vocal  cord 
nfrarimal  portion  of  larynx 

Cricoid  cartilar^e  (cut) 
Ring  of  trachea 


i 


VERTICAL  SEGTIOK  OF  MOUTH,  PHARYNX,  LARYNX, 

212 


^D   NOSE. 


THE  MOUTH.  213 

The  operation  which  is  frequently  perfonne<l  uimii  the  uitper  hp  is  for  cor- 
reetion  of  harelip  whidi  occurs  upon  one  side,  opposite  tlie  interval  between  the 
canine  and  lateral  incisor  teeth  and  not  in  the  median  line,  because  the  central 
])ortion  of  the  lip  with  the  premaxillary  bone  is  formed  by  the  fronto-nasal  process 
of  the  fetus,  whereas  each  lateral  jiortion  of  the  upper  lip  develops  from  the 
maxillary  process  of  the  sujierior  visceral  arch.  The  lower  lip  is  rarely  operated 
u[)on  except  for  extirpation  of  epitheliomata.  These  operations  leave  a  V-shaped 
wt)und,  which  is  closed  by  pins  or  sutures.  The  arteries  divided  are  the  superior 
coronary  or  inferior  coronary  arteries.  During  the  operation  hemorrhage  may  be 
checked  by  an  assistant  grasping  the  lip  at  the  angles  of  the  mouth,  between  the 
thumbs  and  index  fingers.  In  closing  the  wound  the  arteries  are  occluded  by 
pressure  of  one  of  the  pins  or  sutures.  The  pin  or  suture  is  carried  through  the 
tissues  of  the  lip  to  the  mucous  membrane  and  under  the  artery,  then  under  the 
artery  at  the  opposite  side  of  the  wound,  and  outward  through  the  tissues  of  the 
lip.  The  lower  lip  is  occasionally  the  site  of  nevus  or  hypertrophy.  Neurotic 
edema  of  the  lower  lip,  a  condition  seldom  seen,  and  for  which  operation  is  of 
no  avail,  must  not  be  mistaken  for  hypertrophy  of  the  lower  lip. 

The  Cheeks  are  composed  of  five  layers :  the  skin,  the  superficial  fascia 
(which  contains  the  facial  vessels  and  some  branches  of  the  facial  and  trifacial 
nerves),  the  bucco-pharyngeal  fascia,  the  buccinator  muscle,  the  submucous  areolar 
tissues,  and  the  mucous  meml)rane. 

The  bucco-pharyngeal  fascia  covers  the  buccinator  muscle,  and  is  continued 
backward  over  the  constrictor  muscles  of  the  pharynx.  The  submucous  areolar 
tissue  contains  the  buccal  glands,  which  resemble  the  labial  glands.  Two  or  three 
glands  larger  than  the  others  are  situated  between  tJie  buccinator  muscle  and  its 
fascial  covering.  They  are  called  molar  glands,  and  their  ducts  open  into  the  ves- 
tibule of  the  mouth  opposite  the  last  molar  tooth.  Opposite  the  crown  of  the 
second  molar  tooth  of  the  upper  jaw  is  the  papilla,  which  marks  the  orifice  of 
Stenson's  duct. 

The  Mouth  Proper  is  bdundeil  in  front  and  at  the  sides  by  the  teeth  and 
gmns.  Its  roof  is  formed  by  the  hard  and  the  soft  palate,  and  its  floor  by  the 
mucous  membrane  of  the  mouth,  a  large  portion  of  the  tongue,  and  the  mylo- 
byoid  and  genio-hyoid  muscles.  Behind,  it  opens  into  the  pharynx  at  the 
isthmus  of  the  fauces.  When  the  mouth  is  closed,  the  tongue  lies  in  contact 
with  the  palate  and  almost  fills  the  mouth  proper. 

The  Teeth  in  the  human  .subject  appear  as  two  sets  :  The  first  or  temporary  set 
is  present  in  children,  and  numbers  ten  in  each  jaw — viz.,  four  incisors,  two  canines, 
and  four  molars.  The  central  incisors  are  the  first  to  pierce  the  gum,  and  make 
their  appearance  at  the  seventh  niontli.     The  lateral  incisors  soon  follow,  the  last 


214  SURGICAL   ANATOMY. 

of  the  set  to  appear  being  the  posterior  molars,  the  eruption  of  which  whould  occur 
in  the  third  year  or  the  hitter  lialf  of  the  second  year.  The  second  or  permanent 
set  are  sixteen  in  number  in  each  jaw — viz.,  four  incisors,  two  canines,  four  bicus- 
pids or  premolars,  and  six  molars.  The  first  molars  appear  in  tlie  seventh  year ; 
the  middle  incisors  and  then  the  lateral  incisors  soon  follow.  The  third  molars,  or 
wisdom  teeth,  are  the  last  to  pierce  the  gums,  u.sually  at  the  seventeenth  or  eigh- 
teenth year.  When  a  child  is  affected  by  congenital  syphilis,  faulty  nutrition 
affects  the  development  of  the  permanent  teeth,  so  tliat  they  are  not  perfectly 
formed.  These  sj^philitic  teeth  are  uneven,  and  have  a  contracted  and  a  crescent- 
ically  notched  cutting  edge.  The  central  incisors  are  the  most  typical,  and  are  the 
"test teeth  of  Hutchinson." 

When  the  mouth  is  wide  open,  a  ridge  produced  by  the  pterygo-maxillary 
ligament  may  be  seen  ascending  from  just  behind  the  last  molar  tooth  to  the 
hamular  process  of  the  internal  pterygoid  plate  of  the  sjihenoid  bone.  The  hamu- 
lar  process  may  be  felt  as  a  resisting  prominence  a  short  distance  behind  and 
slightly  internal  to  the  upper  last  molar  tooth.  It  is  the  guide  in  division  of  the 
tensor  palati  and  levator  j^alati  muscles. 

The  Gums  cover  the  alveolar  processes  of  the  jaws  and  firmh'  surround  the 
necks  of  the  teeth.  They  are  compo.sed  of  dense  vascular  connective  tissue,  cov- 
ered by  mucous  membrane.  The  periosteum  of  the  alveolar  processes  is  continued 
into  the  alveoli,  forming  the  lining  membrane  of  these  cavities.  Pus  at  the  root 
of  a  tooth  may  work  its  way  into  the  gum,  producing  a  "gum  boil." 

In  chronic  lead  poisoning  a  blue  line  appears  ujjon  the  dental  margin  of  the 
gums,  and  is  produced  by  lead  sulphid,  which  is  formed  hj  chemic  combination 
between  lead  in  the  tissues  and  hydrogen  sulphid  derived  from  decomposing  food. 

Swelling  of  the  gums  and  tenderness  of  the  teeth  during  the  administration 
of  mercury  indicate  that  the  physiologic  limit  for  that  remedy  has  been  reached, 
and  that  the  dose  should  be  decreased  or  the  drug  temporarily  withdrawn. 

The  swollen  and  readily  bleeding  gums  in  scurvy  assist  in  the  diagnosis  of 
that  disease. 

The  Hard  Palate  is  composed  of  the  palate  or  horizontal  processes  of  the 
superior  maxillary  and  palate  bones,  clothed  on  their  inferior  surface  by  a  dense, 
tough  muco-periosteum.  In  the  operation  for  cleft  palate  the  toughness  and  den- 
sity of  the  muco-periosteum  render  its  manipulation  more  difficult.  The  muco- 
perio.steuni  contains  a  median  raphe,  which  marks  the  line  of  junction  of  the  two 
halves.  When  these  two  halves  fail  to  unite,  cleft  palate  results.  This  malforma- 
tion is  often  associated  \\\\\\  hmvlip. 

Bi.oon  Supply. — Tlie  hard  j)alate  is  supplied  by  iiie  naso-palatine  and  poste- 
rior ]i;il;itiiie  vessels. 


THE   MOl'TU.  215 

TIr-  ])i)sti'iior  or  (k'sccinlini;-  |inl;itine  arteries  furnisli  nearly  all  the  nutrition 
of  the  iianl  jialate,  and  lie  in  the  muco-periosteum  near  tlie  alveolar  processes. 
The  ineisiiin  into  the  nineo-jieriostenm  in  the  operation  for  cleft  of  the  hard  palate 
should  be  made  near  and  parallel  with  the  alveolar  processes,  so  that  the  descend- 
ing palatine  arteries  need  not  be  divided  and  may  be  retained  in  the  flaps  to  pro- 
vide for  their  nutrition.  In  dissecting  up  the  flaps  the  operator  should  follow  the 
bone  closely,  as  these  arteries  run  nearer  to  the  bone  than  to  the  free  surface  of  the 
muco-periosteum.  Bleeding  from  the  posterior  palatine  artery  may  be  checked  by 
plugging  the  posterior  palatine  canal,  which  can  be  located  to  the  inner  side  of  the 
last  molar  tooth  with  a  sharp  probe. 

Nerve  Supply. — From  the  naso-palatine  and  great  or  anterior  palatine 
nerves. 

Cleft  palate,  as  previously  stated,  occurs  only  in  the  median  line.  The  cleft 
may  affect  only  the  uvula  and  soft  palate,  or  it  ma}'  extend  forward  through  the 
hard  palate  to  the  anterior  palatine  foramen.  If  the  cleft  extend  forward  beyond 
this  foramen,  it  leaves  the  median  line  and  follows  the  line  of  the  suture  at  the 
side  of  the  premaxillary  bone,  the  anterior  extremity  of  the  cleft  being  between 
the  lateral  incisor  and  the  canine  tooth.  If  the  cleft  follow  one  suture,  single 
harelip  is  u-sually  present,  and  if  it  traverse  both  sutures,  double  harelip  usually 
exists  and  the  premaxillary  bone  is  suspended  by  the  vomer.  In  the  operation  for 
the  correction  of  double  harelip  with  projection  of  the  premaxillary  bone,  the 
author  advises  that  the  attachments  of  this  bone  be  loosened  and  the  bone  be 
pushed  back  in  place  and  not  removed. 

The  Soft  Palate  is  described  with  the  pharynx. 

The  Mucous  Membrane  in  the  floor  of  the  mouth  covers  the  tongue,  a  small 
area  on  each  side  of  that  organ,  and  the  triangular  area  beneath  its  tip  or  free  end. 
In  the  median  line,  as  the  mucous  membrane  is  reflected  upon  the  under  surface 
of  the  tongue,  it  forms  a  fold — the  frasnum  linguae.  In  some  infants  the  frwnum 
linguje  is  so  short  that  it  interferes  with  sucking,  and  later  prevents  distinct 
articulation.  To  relieve  these  cases  it  is  necessary  to  divide  the  frenum  by  snip- 
ping its  free  margin  with  blunt  scissors  close  to  the  floor  of  tlie  mouth  and  then 
tearing  it.  This  method  is  adopted  to  avoid  division  of  the  artery  of  the 
frenum,  with  consequent  annoying  hemorrhage.  On  each  side  of  the  frenum 
are  the  small  papilke,  w'hich  contain  the  orifices  of  Wharton's  ducts.  The 
rounded  elevation  on  each  side  of  the  lingual  frenum  is  produced  by  the  sub- 
lingual glands,  which  lie  immediate^  beneath  the  mucous  membrane.  The 
orifices  of  tlie  ducts  of  Rivini  are  situated  ujion  these  elevations.  In  the  floor 
of  the  mouth,  opposite  the  second  molar  tooth,  the  lingual  nerve  may  be  felt  and 
divided  to  relieve  pain  in  the  tongue  ;  when  the  tongue  is  drawn  out  of  the  mouth 


216  SURGICAL  ANATOMY. 

and  toward  the  opposite  side,  a  ridge  in  tlie  nmeous  membrane  of  the  floor  of  the 
mouth,  jiroduced  by  this  nerve,  is  seen  extending  forward  from  the  inner  side  of 
the  last  molar  tooth. 

A  cj'stic  tumor  in  the  floor  of  the  mouth  due  to  occlusion  of  the  orifice  of 
Wharton's  duct,  one  of  the  ducts  of  Eivini,  or  the  duct  of  a  mucous  follicle,  is 
called  a  raiiula. 

The  sublingucd  bursa,  according  to  Tillaux,  is  found  immediately  beneath  the 
mucous  mend)rane  of  the  anterior  part  of  the  floor  of  the  mouth,  where  the 
mucous  membrane  is  reflected  upon  the  posterior  surface  of  the  lower  jaw.  This 
bursa  is  aftected  in  acute  ranula. 

The  Tongue  is  a  freely  movable,  muscular  organ,  covered  with  mucous  mem- 
brane. It  contains  the  organs  of  tlie  special  sense  of  taste,  and  is  an  important 
accessory  in  the  functions  of  mastication,  deglutition,  and  speech. 

The  mucous  membi-ane  covers  all  the  free  surface  of  the  tongue — i.  e.,  the 
dorsum,  sides,  and  le.ss  than  the  anterior  one-third  of  the  under  surface  of  the 
organ. 

Tlie  tongue  has  a  tij),  a  base,  a  dorsum,  and  two  sides. 

The  tip  or  apex  of  the  tongue  is  its  most  movable  portion,  and  is  covered  on 
both  its  upper  and  lower  surface  by  mucous  membrane.  Its  range  of  motion  is 
influenced  by  the  length  of  the  frsenum  lingua?.  A  short  frenum  cau.ses  tongue-tie, 
and  a  long  one  allows  the  tongue  to  fall  backward. 

The  base  or  root  of  the  tongue  is  its  least  movable  portion.  It  is  attached  to 
the  hyoid  bone  by  muscular  tissue  and  Ijy  a  fibrous  membrane  {hypo-glossal  mem- 
braiu) ;  to  the  anterior  portion  of  the  lower  jaw,  at  the  side  of  the  symphysis,  by 
the  genio-hyo-glossus  muscle  ;  and  to  the  epiglottis,  by  the  three  glosso-epiglot- 
tidean  iblds  of  mucous  membrane. 

The  median  glosso-epiglottidean  fold  is  sharply  outlined,  and  has  been 
called  the  freenum  epiglottidis.  Tlie  lateral  glosso-epiglottidean  folds  are 
rounded  and  indistinct.  Between  the  median  an<l  the  lateral  folds  are  the  glosso- 
epiglottidean  pouches  or  vallecul£e,  in  which  small  foreign  bodies  may  lodge  and 
cau.se  nuu'li  discomfort. 

The  dorsum  of  the  tongue  is  convex  and  grooved  in  the  median  line,  forming 
a  raphe  from  which  a  septum  dips  down  between  the  muscles  of  the  two  sides. 
The  raphe  terminates  behind  at  the  foramen  caecum,  which  is  the  orifice  of  the 
oljliterated  thyro-glossal  duct.  In  tlie  fetus  the  thyro-glossal  duct  extends  from 
tile  middle  lobe  of  the  thyroid  gland  t<i  the  tongue.  It  can  seldom  l)e  traced  in 
tlie  adull.  Tiie  ])osterior  one-third  of  tin'  dorsum  of  the  tongue  dips  downward  in 
front  of  the  pharynx  almost  to  the  level  of  the  hyoid  bone,  and  overhangs  the 
epiglottis.     It  presents  no  papilhe,  but  has  a  somewhat  uneven  surface,  jiroduced 


PLATE  XLIX, 


Vocal  process  of  arytenoid  cartilage 
True  vocal  cord 
Sinus  pyriformis 


Interarytenoid  fold 

Posterior  wall  of  pharynx 

Corniculum  laryngis 

Cuneiform  cartilage 

Aryteno-epiglottidean  fold 


False  vocal  cord 
Ventricle  of  larynx 


Lateral  glosso-epiglottidean 
fold 


Median  (rlosso-epifflottidean 
fold 


Adenoid  tissue  at 
base  of  tongue 


Foramen  caecum 


Circumvallate  papillae 
Fungiform  papillae 


SUPERIOR  APERTURE  OF  LARYNX  AND 
218 


OF  TONGUE. 


THE  MOUTH.  219 

by  tin;  irn'<;iilar  fdUcctinn  dI'  lyiiiiilmiil  tissue,  known  as  tlio  Ungual  tonsil. 
W'Ik'U  tlic  liumial  tunsil  is  nuich  cnlartii'd,  it  may  depress  tlie  epiglottis  and  cause 
ditticult  respiration.  Un  tlic  antciior  two-thirds  of  the  dorsum  of  the  tongue  the 
mucous  membrane  contains  numerous  papillte,  whicli  are  of  tlu'ce  varieties:  fili- 
form, fungiform,  and  circumvallate. 

The  filiform  papillae  are  the  smallest  and  most  numerous.  They  are  long, 
slender,  conic,  and  branched  at  their  free  ends.  ,  Fur  on  the  tongue,  or  coated 
tongue,  is  due  to  increase  in  the  thickness  of  the  epithelium  upon  tliese  papillae. 
Fur  on  the  tongue  is  present  in  indigestion,  constipation,  high  fever,  contagious 
and  infectious  diseases,  when  large  abscesses  are  present,  or  in  the  various  forms 
of  ptomain  poisoning. 

The  fungiform  papillse  are  more  numerous  than  the  circumvallate  papillae. 
They  resemble  small  knobs,  and  are  the  red  spots  best  observed  on  tiie  sides  and 
anterior  portion  of  the  dorsum  of  the  tongue. 

The  circumvallate  papillae,  numbering  from  eight  to  twelve,  are  situated  at 
the  junction  of  the  posterior  with  the  middle  one-third  of  the  dorsum  of  the  tongue. 
They  form  a  letter  V,  its  apex  being  directed  backward  toward  the  foramen  ctecum. 
They  are  surrounded  by  an  elevated  margin  or  vallum,  so  that  the  papilla?  rest  in 
pits.     They  contain  the  special  taste  organs. 

On  the  sides  of  the  tongue  the  mucous  membrane  is  smooth,  except  at  the 
posterior  part,  just  in  front  of  the  attachment  of  the  anterior  pillars  of  the  fauces, 
where  there  are  several  parallel  folds,  known  as  the  papillas  foliata.  The  papillae 
foliata  are  best  developed  in  some  of  the  lower  animals,  and  contain  taste  organs. 

The  under  surface  of  the  tongue,  Ijeliind,  receives  the  insertion  of  its  extrinsic 
muscles,  but  in  front  it  is  free  and  covered  bj'  smooth,  thin  mucous  membrane, 
through  which  the  commencement  of  tlie  lingual  vein  can  be  seen  on  each  side  of 
the  median  line.  These  veins  are  so  superficial  that  they  may  be  injured  in 
division  of  the  lingual  frenum  for  tongue-tie. 

The  glands  of  the  tongue  are  found  in  the  mucous  membrane  of  the  poste- 
rior tliird  of  the  dorsum  and  at  the  sides  of  the  organ.  They  ai'e  most  numerous 
around  the  circumvallate  pajiillce.  Those  in  relation  with  the  taste  buds  secrete  a 
serous,  and  the  others  a  mucous,  fluid.  Embedded  in  the  substance  of  the  lower 
surface  of  the  tongue,  near  the  tip  of  the  organ,  is  a  collection  of  mucous  glands, 
about  the  size  of  a  pea ;  this  is  the  so-called  gland  of  Nuhn  or  Blandin  ;  occlusion 
of  the  duct  of  these  glands  may  cause  the  formation  of  a  retention  cyst. 

DissECTKix. — To  study  the  arrangement  of  tbe  muscles  of  the  tongue  it  is 
necessary  to  remove  the  mucous  membrane  from  one  side  of  it. 

The  muscles  of  the  tongue  compose  the  greater  part  of  its  mass,  and  are 
divided  into  an  extrinsic  and  an  intrinsic  group.     The  extrinsic  muscles  are  the 


220  SURGICAL  ANATOMY. 

stylo-glossus,  hyo-glossus,  a  small  portion  of  the  superior  constrictor  muscle  of  the 
pharynx,  palato-glossus,  and  genio-hyo-glossus. 

The  stylo-glossus  muscle  runs  along  the  side  of  the  tongue  to  its  tip.  The 
hyo-glossus  muscle  is  inserted  internal  to  the  stylo-glossus  muscle.  The  superior 
constrictor  muscle  of  the  pharynx  is  seen  arising  from  the  side  of  the  base  of  the 
tongue.  The  palato-glossus  muscle  is  continuous  with  the  transverse  fibers  of  the 
intrinsic  muscular  tissue  of  the  tongue.  The  genio-hyo-glossus  muscle  is  next 
to  the  median  line,  and  is  separated  from  the  genio-hyo-glossus  of  the  opposite  side 
by  the  septum  linguse  and  hypo-glossal  membrane. 

The  intrinsic  or  lingualis  muscle  contains  longitudinal,  transverse,  and  vertical 
fibers.  The  longitudinal  fibers  are  composed  of  two  separate  bundles  on  each 
side,  a  superior  and  an  inferior.  The  superior  lingualis  muscle  lies  beneath  the 
mucous  membrane  of  the  dorsum,  and  extends  from  the  base  to  the  apex  of  the 
tongue.  It  is  separated  from  the  superior  lingualis  of  the  opposite  side  by  the 
septum  linguse.  The  inferior  lingualis  muscle  is  found  on  the  under  surface  of 
the  tongue,  beneath  the  transverse  fibers.  It  is  attached  behind  to  the  hyoid 
bone,  and  extends  from  the  base  of  the  tongue  to  its  apex.  Behind,  it  lies 
between  the  hyo-glossus  and  the  genio-hyo-glossus  muscle,  and  in  front,  be- 
tween the  stylo-glossus  and  the  genio-hyo-glossus  muscle.  The  transverse  fibers 
form  a  thick  layer  beneath  the  superior  lingualis  muscle,  and  extend  from  the 
septum  lingufe  to  the  side  of  the  tongue.  The  vertical  fibers  decussate  with  the 
transverse  fibers,  and  pass  in  curved  lines  from  the  dorsum  to  the  inferior 
aspect  of  the  tongue.  As  the  tongue  is  almost  entirely  composed  of  muscular 
tissue  and  contains  little  areolar  tissue,  it  docs  not  become  much  swollen  when 
inflamed. 

Many  of  the  muscular  fibers  of  the  tongue  are  attached  to  the  mucous  mem- 
brane ;  hence,  when  the  mucosa  is  destroyed,  as  in  ulcerative  processes,  the  surface 
of  the  ulcer  presents  an  uneven,  ragged  appearance,  due,  in  part,  to  retraction  of 
the  muscular  fibers. 

Tlie  septum  linguas  is  a  fibrous  nicmbrane  which  extends  vertically  down- 
ward from  tlie  median  raphe  between  tlie  lialves  of  the  tongue,  and  separates  the 
two  lingualis  and  the  two  genio-hyo-glossus  muscles.  Its  lower  portion  is  strong, 
attaclios  the  base  of  the  tongue  to  the  hyoid  bone,  and  is  called  the  hypo-glossal 
membrane. 

Paralysis  and  atrophy  of  one-half  of  the  tongue  may  be  produced  liy  a  cen- 
tral lesion  of  the  hypo-glossal  nerve,  as  by  a  hemorrhage  affecting  the  centi'r  of 
that  iiei've  in  the  medulla  oMongata,  or  In'  a  ])erij)lu'ral  lesion,  as  disease  or  frac- 
ture of  the  occipital  bone  at  the  anterior  condyloid  foramen  or  liy  pressure  fiom 
an  aneurvsm  of  the  external  carotid  or  internal  carotid  arterv. 


I 


PLATE  L. 


/Mucous  membrane 
/Submucous  tissue 
.Septum 
/Superior  lingualis  m. 


Vertical  and  transverse  muscular  fibres 


Extrinsic  muscular  fibres 


Inferior  lingualis  m. 
Vena  comes 
Ranine  a. 
Vena  comes 


TRANSVERSE  SECTION  OF  ONE-HALF  OF  TONGUE. 
221 


■    THE  MOUTH.  223 

Macroglossia,  or  l;n\i;'o  Idiinue,  is  usually  due  to  increased  development  of 
the  lynqilioid  tissue  of  tlie  tontiue. 

Blood  Supply. — The  nutritinn  of  the  tonjiue  is  derived  from  the  lingual, 
facial,  and  ascending  ])haryngeal  arteries. 

Nerve  Ir^rn'i.v. — From  the  glosso-pharyngeal,  hyiio-glossal,  lingual,  and 
chorda  tympani  ni'rves.  The  glosso-pharyngeal  is  the  nerve  of  the  special  sense  of 
taste,  and  supplies  special  sensory  and  conunon  st'nsory  tiljcrs  to  the  mucous  mem- 
brane at  the  posterior  third  of  the  tongue,  and  to  the  circumvallate  pajiillre.  The 
hypo-glossal  is  the  motor  nerve,  and  supplies  the  extrinsic  muscles  and  the  lingualis 
muscle,  the  latter  being  also  supplied  by  the  chorda  tympani  nerve.  The  lingual, 
or  gustatoiy,  is  the  common  sensory  nerve  of  the  tongue,  and  supplies  the  front 
and  sides  of  that  organ.  Small  branches  of  the  superior  laryngeal  nerve  are  dis- 
tributed to  the  base  of  the  tongue  in  the  region  of  the  epiglottis. 

Irritation  of  the  lingual  nerve,  as  liy  an  ulcer  or  a  carcinoma  of  the  tongue, 
may  cause  reflected  disturbance  in  the  tissues  supj)lied  by  other  branches  of  the 
inferior  maxillary  nerve — through  the  auriculo-temporal  nerve,  pain  in  the  pinna, 
external  auditory  meatus,  and  temporal  region  ;  through  the  inferior  dental  nerve, 
pain  in  the  lower  teeth,  lower  gums,  and  chin  ;  and  through  the  motor  branches 
of  the  inferior  maxillary  nerve,  spasm  of  the  muscles  of  mastication,  excepting  the 
buccinator  muscle. 

In  profound  anesthesia  relaxation  of  the  tissues  allows  the  tongue  to  fall 
backward,  depress  the  epiglottis,  and  obstruct  respiration.  To  relieve  this  condi- 
tion the  anesthetizer  carries  the  lower  jaw  forward  by  placing  his  fingers  behind 
the  angles  of  that  bone.  This  procedure  makes  tension  upon  the  genio-hyo-glossus, 
genio-hyoid,  and  mylo-liyoid  muscles,  tlie  hypo-glossal  membrane,  the  glosso-epi- 
glottidean  folds,  and  the  hyo-epiglottidean  ligament ;  draws  the  tongue,  epiglottis, 
and  hyoid  bone  forward ;  and  opens  the  superior  ajierture  of  the  larynx. 

The  lymphatic  vessels  of  the  lips  pass  with  the  superficial  lymphatic  vessels 
of  the  front  of  the  face  into  the  submaxillary  and  superior  deep  cervical  lymphatic 
glands. 

The  lymphatics  of  the  roof  of  the  mouth  and  deeper  portion  of  the  cheek 
terminate  in  the  internal  maxilhny  lym])hatic  glands. 

The  lymphatics  of  the  floor  of  the  mouth  and  anterior  part  of  the  tongue 
pierce  the  mylo-hyoid  muscle  and  join  the  submaxillary  lymphatic  glands. 

The  lymphatics  of  the  tongue,  excejiting  those!  of  tlie  most  anterior  portion, 
accompany  tiie  lingual  vein,  pa.ss  throngli  the  lingual  lymi)liatic  glands  on  the 
hyo-glossus  muscle,  and  terminate  in  the  superior  deep  cervical  glands. 

In  excision  of  the  tongue  for  carcinoma  it  is  advi-sable  to  remove  the  superior 


224  SURGICAL  ANATOMY. 

deep  cervical,  submaxillary,  and  lingual  lym{)liatic  glands,  so  that  the  involved 
glands  may  not  be  the  source  of  a  secondary  growth.  Occasionally  the  submaxil- 
lary salivary  gland,  which  contains  two  or  more  lymphatic  glands,  should 
also  be  removed. 

The  isthmus  of  the  fauces  is  the  large  orifice  of  communication  between  the 
mouth  and  the  pharynx.  It  is  bounded  above  by  the  soft  palate,  below  by  the 
base  of  the  tongue,  and  on  each  side  by  the  pillars  of  the  fauces. 

The  under  surface  of  the  Soft  Palate,  which  is  seen  through  the  mouth,  is 
concave,  and  its  mucous  membrane  is  continuous  with  that  of  the  hard  palate.  It 
presents  a  median  raphe  which  marks  the  line  of  union  of  the  halves. 

The  Uvula  is  the  conic  process  which  is  suspended  in  the  isthmus  of  the 
fauces  from  the  middle  of  the  free  border  of  the  soft  palate. 

The  pillars  of  the  fauces,  or  pillars  of  the  soft  palate,  are  ridges  in  the 
mucous  membrane  which  extend  outward  and  downwanl  from  the  uvula.  There 
are  two  pillars  on  each  side — an  anterior  and  a  posterior  pillar.  The  anterior  pil- 
lars extend  downward,  outward,  and  forward  to  the  sides  of  the  base  of  the 
tongue.  They  contain  the  palato-glossus  muscles.  The  posterior  pillars  are 
directed  downward,  outward,  and  Ixickward,  and  fode  away  upon  the  lateral  wall 
of  the  pharynx.  The}'  are  produced  by  the  palato-pharyngeus  muscles.  A 
triangular  depression  exists  on  each  side  between  the  anterior  and  the  posterior 
pillar,  and  is  termed  the  recess  of  the  fauces,  or  tonsillar  recess. 

The  Tonsils  are  two  oblong  rounded  bodies,  situated  in  the  recesses  of  the 
fauces.  They  vary  in  size  in  different  individuals,  but  should  uot  project  beyond 
the  anterior  pillars  of  the  fauces.  The  internal  surface  of  the  tonsil  is  covered 
by  the  oral  mucous  memlirane,  and  presents  from  ten  to  fifteen  puncture-like 
orifices,  which  lead  into  recesses  called  crypts.  The  crypts  are  lined  by  exten- 
sions of  the  oral  mucous  membrane.  The  tonsils  are  compound  follicular  glands 
— i.  e.,  they  contain  a  number  of  aggregations  of  lymphoid  tissue  similar  to 
that  of  the  solitary'  glands  of  the  intestines.  They  are  enveloped  by  a  fibrous 
capsule.  The  secretion  of  the  tonsil  is  derived  from  the  mucous  glands  in 
tlie  mucous  membrane  lining  the  crypts,  and  contains  numerous  epithelial  and 
lymphoid  cells. 

Inspissation  of  the  mucous  secretion  in  the  crypts  of  the  hypertrophied 
tonsils  gives  rise  to  the  forma tiim  of  cheesy  jilugs,  which  contain  decomposing 
epithelium,  emit  a  foul  odor,  and  ])roduce  fetid  breath. 

It  is  quite  probable  tliat  germs  in  the  stagnant  secretion  in  the  crypts  of 
the  tonsils  enter  the  lymphatic  vessels,  and  cause  many  of  the  cases  of  inflam- 
mation and  tuberculosis  of  the  deep  cervical  chain  of  lymphatic  glands. 

Blood  Supri.v. — From  the    ascending   pharvngeal    branch    of    the    external 


I 


THE   MOCTIf.  225 

carotid,  the  tonsillar,  and  ascending  palatine  branches  of  the  facial  artery,  the 
dorsalis  lingute  branch  of  the  ling-ual  artery,  and  the  descending  jialatine  branch 
of  the  internal  maxillary  artery. 

Neuve  Supply. — From  the  glosso-pharyngeal  nerve  and  branches  of  Meckel's 
gaugliiin. 

The  veins  of  the  tonsils  em]ity  into  the  tonsillar  plexus,  which  lies  on  the 
outer  surface  of  the  gland  and  is  drained  by  the  pharyngeal  veins. 

The  lymphatics  of  the  tonsil,  which  are  numerous,  empty  into  the  lynn>halic 
glands  near  the  angle  of  the  lower  jaw,  and  into  the  superior  deep  cervical  lym- 
phatic glands. 

Kelatioxs. — Externally,  the  tonsil  is  in  relation  with  the  superior  con- 
strictor muscle  of  the  pharynx  and  the  pharyngeal  aponeurosis,  which  separate  it 
from  the  internal  carotid  and  the  ascending  pharj'ngeal  artery  ;  internally,  with 
the  mueons  membrane  of  the  mouth  and  pharynx. 

Tonsillitis. — The  tonsils  are  frequently  affected  by  inflammation.  In  follic- 
ular tonsillitis  the  crypts  especially  are  involved,  and  their  secretion  is  inspissated, 
forming  yellowish-white  pilugs  which  resemble  diphtheric  false  membrane,  and 
give  the  throat  the  appearance  of  "ulcerated  sore  throat."  In  phlegnionuus  or 
jiurulent  tonsillitis  (cjuinsy),  when  the  affection  is  bilateral,  the  tonsils  may  almost 
meet  in  the  median  line.  These  tonsillar  abscesses  should  be  incised  with  a  bis- 
toury, guarded  to  avoid  injuring  the  tongue.  The  knife  should  be  directed  back- 
ward and  inward,  and  the  incision  be  made  toward  the  median  line  to  avoid 
injuring  tlie  internal  carotid  artery,  which  lies  just  external  to  the  gland. 

Hypertrophied  tonsils  can  not  be  felt  externally  below  the  angles  of  the 
lower  jaw,  for  the  reason  that  the  pharyngeal  aponeurosis  and  the  superior 
constrictor  muscles  of  the  pharynx  prevent  the  tonsils  from  projecting  outward. 
The  masses  present  in  these  locations  are  enlarged  lymphatic  glands  which 
receive  lymphatic  vessels  from  the  tonsils.  Hypertrophied  tonsils  project  beyond 
the  pillars  of  the  fliuces,  and  cause  considerable  annoyance  through  their  inter- 
ference with  respiration  and  with  the  resonance  of  the  voice.  Hypertrophied 
tonsils  should  be  amputated  with  a  tonsillotome,  or  removed  by  dissection. 
Exaggerated  prominence  of  the  anterior  pillars  of  the  fauces  may  render  these 
operations  quite  difficult.  The  relation  which  the  tonsil  bears  to  the  internal 
carotid  and  ascending  pharyngeal  arteries  should  be  borne  in  mind  in  either 
of  these  operations. 

The  ascending  pharyngeal  artery  runs  upon  the  external  surface  of  the  supe- 
rior constrictor  muscle  of  the  pharynx,  opposite  the  tonsil,  and  in  operations  upon 
the  tonsil  or  in  wounds  of  that  organ  is  in  more  danger  of  being  injured  than  is 
the  internal  carotid  artery,  which  is  placed  further  back. 

S—    11—15 


22G  SURGICAL  ANATOMY. 

Malignant  growths  of  the  tonsil  are  not  infrequent,  and  are  best  reniove<l 
through  an  incision  made  along  the  anterior  border  of  tlie  sterno-nuistoid  muscle 
and  not  through  the  mouth,  because  the  involved  Ij'mphatic  glands  can  not  be 
satisfactorily  reached  by  the  latter  route. 

The  Bucco-pharyngeal  Fascia  is  a  thin  layer  of  deep  fascia  which  covers  the 
buccinator  muscle  and  the  constrictor  muscle  of  the  pharynx.  It  is  contiiuious 
below  with  the  delicate  fibrous  investment  of  the  esophagus. 

Dissection. — Stutf  the  pharynx  and  esophagus  with  cotton,  and  cai'cfully 
remove  the  fascia  covering  the  esophagus,  trachea,  and  the  constrictor  muscles 
of  the  pharynx.  The  ascending  pharyngeal  artery,  which  is  in  relation  with 
the  superior  constrictor  nmscle  of  the  iiharynx,  and  the  recurrent  laryngeal 
nerve,  which  lies  in  the  groove  between  the  esophagus  and  trachea,  are  the  struc- 
tures most  likely  to  be  destroyed. 

The  Esophagus  is  the  narrow  continuation  of  the  pharynx.  It  begins  at  the 
lower,  contracted  end  of  the  pharynx,  opposite  the  sixtli  cervical  ^-ertebra  and  the 
lower  border  of  the  cricoid  cartilage.  It  passes  downward  behind  the  trachea,  to 
enter  the  posterior  mediastinum  of  the  chest.  At  its  l.Teginning  it  lies  in  the 
median  line,  but  at  the  lower  part  of  the  neck  it  inclines  to  the  left  side.  Its  mus- 
cular coat  is  seen  to  be  continuous  with  the  inferior  constrictor  muscle  of  the 
pharynx. 

Relations. — In  front  of  the  esophagus,  in  the  neck,  are  the  trachea,  left  re- 
current laryngeal  nerve,  and  the  posterior  surface  of  the  left  lobe  of  the  thyroid 
gland.  Behind  it  are  the  prevertebral  fascia,  the  bodies  of  the  vertebra^,  and  the 
longus  coli  muscles.  On  its  right  side  are  the  right  carotid  sheath  and  its  contents, 
the  right  recurrent  laryngeal  nerve,  and  the  right  lobe  of  the  thyroid  gland.  On 
its  left  side  are  the  left  carotid  sheath,  the  left  common  carotid  and  subclavian 
arteries,  the  left  recurrent  laryngeal  nerve,  the  thoracic  duct,  and  the  left  lobe  of 
the  thyroid  gland. 

The  narrowest  point  in  the  esophagus  is  behind  the  lower  border  of  the  cricoid 
cartilage  and  in  front  of  the  sixth  cervical  vertebra.  Tliis  is  the  point  at  which  a 
large  foreign  body,  such  as  a  set  of  false  teeth,  would  Ix-  likely  to  lodge.  If  a 
foreign  body  can  not  be  withdrawn  througli  the  mouth  or  jiushed  into  the  stomach, 
it  becomes  necessary  to  perform  an  esojihagotomy.  This  is  done  as  follows :  An 
incision  is  made  along  the  anterior  border  uf  the  left  sterno-mastoid  muscle,  cutting 
skin,  superficial  fascia,  platysma  myoides  muscle,  some  superficial  vessels  and 
nerves,  superficial  layer  of  the  deep  fascia,  omo-hyoid  muscle  if  necessary,  pre- 
tracheal fascia,  and  esophagus.  The  carotid  sheath  and  its  contents  must  be  dis- 
placed outward  ;  the  trachea,  thyroid  gland,  and  sterno-thyroid  and  sterno-hyoid 
muscles  should  be  displaced  inward.     The  sui)erior  and  middle  thyroid  veins  nuist 


THE  PlIARYSX.  227 

1)0  avt.tiiKMl  nr  diviilcil   between  liuaturrs,  and  the  ix'currcnt  laryngeal  nerve  and 
inferior  tliyniid  artery  must  nut  be  iiijurrd. 

The  tluiraeie  jiurtion  iif  the  esophayus  will  be  described  with  the  chest. 


THE  PHAEYNX. 

The  pharynx,  the  second  jiortion  of  the  alimentary  tract,  is  situated  behind  the 
nasal  cavities,  the  mouth,  and  the  larynx  ;  it  is  subdivided  into  the  naso-pharynx, 
oro-pliarynx,  and  laryngo-pharynx,  and  is  a  conic,  musculo-membranous  tube.  TIjc 
naso-pharynx  and  oro-pharynx  bridge  the  gap  in  the  respiratory  tract  between 
the  larynx  and  nasal  cavities,  and  assist  in  giving  resonance  to  the  voice;  the 
oro-pharynx  and  laryngo-pharynx  coiniect  the  nioutli  with  the  esophagus,  and 
carry  the  food  from  the  former  to  the  latter.  The  pharynx  is  about  four  and  one- 
half  inches  in  length,  and  extends  from  the  base  of  the  skull  to  the  upper  border 
of  the  sixth  cervical  vertebra,  opposite  the  lower  border  of  the  cricoid  cartilage, 
where  it  becomes  the  esophagus.  The  base  of  the  cone  is  in  contact  with  the 
under  surface  of  the  body  of  the  splienuid  bone  and  the  basilar  process  of  the 
occipital  bone,  and  its  apex  blends  with  the  esophagus.  The  pharynx  is  com- 
pressed from  before  backwai'd,  the  transverse  diameter  being  greater  than  the 
antero-posterior.  Its  widest  point  is  opposite  the  greater  cornua  of  the  hyoid  bone, 
whei'e  it  is  about  two  inches  in  width  ;  its  nari'owest  point  is  at  its  junction  with 
the  esophagus,  opposite  the  lower  border  of  the  cricoid  cartilage,  where  it  is  about 
three-fourths  of  an  inch  wide. 

Although,  owing  to  the  dilatability  of  the  pharynx,,  large  foreign  bodies  may 
be  retained  in  it  for  a  long  time  without  producing  much  discomfort,  they  more 
frecjuently  give  rise  to  alarming  symptoms.  They  usually  lodge  at  the  lower  end, 
which  is  the  narrowest  portion  of  that  canal.  Here  they  lie  behind  the  larynx, 
causing  dyspnea  and  obstructing  deglutition.  In  attempting  ivmoval  of  these 
bodies  it  is  important  to  remember  that  the  iiharyngo-esophageal  junction  is  about 
six  inches  from  the  teeth. 

Foreign  bodies  in  the  pharynx  may  cause  suffocation  by  occlusion  of  the  supe- 
rior aperture  of  the  larynx,  or  by  producing  spasm  of  the  muscles  of  the  larynx. 
In  either  condition  sudden  death  may  occur  during  eating.  As  the  mass  of  food 
can  be  reached  if  it  rests  upon  the  superior  aperture  of  the  larynx,  the  proper 
course  of  procedure  is  to  remove  it  with  the  finger  used  as  a  liook. 

The  pharynx  has  a  nuiscular,  a  fibrous,  and  a  mucous  coat. 

The  Muscular  Coat  of  the  Pharynx  is  composed  of  three  nmscles — viz.,  the 


228  SURGICAL  ANATOMY. 

inferior,  middle,  and  superior  constrictor  muscles, — with  a  few  fibers  from  the  stylo- 
pharyngeus  and  palato-pharyngeus  muscles. 

The  constrictor  muscles  of  the  pharynx  are  flat,  and  are  inserted  into  the 
median  raphe  on  the  posterior  aspect  of  the  organ.  This  raphe  is  formed  by  the 
interlacing,  tendinous  fibers  of  the  muscles  of  the  opposite  sides,  and  extends  down- 
ward from  the  pharyngeal  sjaine  on  the  basilar  process  of  the  occii>itaI  bone.  The 
constrictor  muscles  are  arranged  so  that  the  inferior  overlaps  the  middle,  and  the 
middle  overlaps  the  superior. 

The  wferior  constrictor  muscle  of  the  pharynx  arises  from  the  posterior  part  of 
the  side  of  the  cricoid  cartilage  behind  the  crico-thyroid  muscle,  from  the  inferior 
cornu,  the  oblique  line,  and  the  superior  l)onler  of  the  ala  of  the  thyroid  cartilage. 
Its  fibers  diverge  as  they  pass  backward  around  the  pharynx,  to  be  inserted  into 
the  median  raphe.  The  lower  fillers  are  almost  horizontal,  and  are  continuous 
with  the  muscular  coat  of  the  esophagus.  The  upper  fibers  ascend  obliquely  over 
the  lower  portion  of  the  middle  constrictor  muscle,  to  be  inserted  into  the  raphe 
higher  up.  Passing  beneath  or  through  the  lower  border  of  the  inferior  constrictor 
muscle  at  its  origin  are  the  recurrent  laryngeal  nerve  and  the  inferior  laryngeal 
brancli  of  the  inferior  tliyroid  artery  on  their  way  to  the  larynx. 

The  middle  constrictor  muscle  of  the  jihariphr  has  a  narrow  origin  from  the  stylo- 
hyoid ligament,  the  lesser  cornu  of  the  liynid  Ijone,  and  the  entire  length  of  the 
upper  surface  of  the  greater  cornu  of  the  hyoid  bone.  Its  fibers  diverge  as  they 
pass  to  the  back  of  the  pharynx,  to  reach  tlie  median  raphe.  The  lower  fibers  are 
almost  horizontal,  and  pasg  beneath  the  upper  part  of  the  inferior  constrictor 
muscle.  The  upper  fibers  pass  oblicjucly  upward  over  the  lower  part  of  the 
superior  constrictor  muscle,  to  reach  the  raphe  near  the  base  of  the  skull.  Some 
of  its  tendinous  fibers  continue  upward  to  the  pharyngeal  spine  on  the  basilar 
process  of  the  occipital  bone. 

In  the  interval  between  the  origins  of  the  middle  and  inferior  constrictor 
muscles,  the  infernal  laryngeal  branch  of  the  superior  laryngeal  nerve  and  the  sujierior 
laryngeal  artery  pierce  the  thyro-hyoid  membrane.  Near  the  upper  margin  of  tlie 
middle  constrictor  muscle  runs  tlie  glosso-pliaryngeal  nerve,  and  passing  beneath 
that  margin  is  the  stylo-pharyngeus  muscle.  Its  origin  is  covered  by  the  hyo- 
glossus  muscle  and  the  lingual  artery,  wiiicli  lies  between  the  hyo-glossus  and  the 
middle  constrictor  muscle. 

Dissection. — To  expose  the  origin  of  tlie  superior  constrictor  muscle  it  is 
necessary  to  remove  the  internal  pterygoid  muscle.  In  removing  tiie  origin  of  that 
muscle  from  the  pterygoid  fos.sa  preserve  the  tensor  palati  muscle,  wliicli  lies 
between  the  internal  pterygoid  muscle  and  llic  internal  pterygoid  plate. 

Tlie  superior  constrictor  muscle  is  a  thin,  pale,  ([uadrilateral  muscle.     It  arises 


PLATE  LI. 


Ophthalmic  a 
iternal  carotid  a 


Sympathetic  n 
Internal  carotid  a 


Superior  cervica 
sympathetic  ganglion 


Ascending  pharyngeal  a 


External  carotid  a 


Common  carotid  a 


Lateral  lobe  of  thyroid  body 


Inferior  thyroid  a 


Recurrent  laryngeal  n. 


Trachea 


Middle  constrictor  m. 


Pharyngeal  aponeurosis 
and  sinus  of  Morgagni 
Buccinator  m. 

-Pterygo-maxillary 
ligament 

Superior  constrictor  m. 


Raphe 
Stylo-pharyngeus  m. 


Tip  of  greater  cornu  of  hyoid  bone 


Inferior  constrictor  m. 


Circular  muscular  fibres  of  esophagus 


Longitudinal  muscular  fibres  of  esophagus 


CONSTRICTOR  MUSCLES  OF  PHARYNX. 
229 


THE   I'lIAUYNX.  231 

from  till'  lowiT  uiu'-tliinl  nf  the  [HLsterior  ImnK'r  of  the  iutrrnal  ])ltTy,t;x)iil  iilate, 
froiu  the  lianiuhir  pnicess  uf  tliat  phiti',  the  iiterv.s^cvuiaxiHary  liganu'ut,  tlio 
postoriiii'  part  of  the  iiiylo-hyoid  riilnv  of  the  lower  jaw,  ami  the  side  of  the 
base  of  the  toiii;-ue.  its  lihers  pass  haekwai'il  to  he  inserted  into  the  median 
raphe.  The  lower  fibers  are  overlapped  hy  the  middle  constrictor  muscle. 
The  upper  fibers  curve  uiiward,  and  have  a  tendinous  attachment  to  the 
pliaryuii'eal  s[>ine  on  the  basilar  ]iroeess  of  the  oeeipiilal  bone.  The  upper 
margin  is  erescentii',  and  situated  some  distance  from  the  base  of  the  .skull, 
k'aving  a  semilunar  interval — the  sinus  of  Morgagni.  Tlie  floor  of  the  sinun 
(if  Margarinl  is  formed  by  the  pharj'ugeal  aponeurosis.  The  upper  border  of 
the  superior  constrictor  muscle  of  the  pharynx  is  in  relation  with  the  levator 
l>alati  nmsele  and  the  Eustachian  tube.  Tlie  superior  constrictor  muscle  with 
the  pharyngeal  ajioueurosis  separate  the  ascending  pharyngeal  and  internal 
carotid  artei'ies  from  the  tonsil. 

Nerve  Suri'i.v. — The  constrictor  muscles  of  the  pharynx  derive  their  nerve 
supply  from  the  jiharyngeal  plexus.  The  interior  constrictor  muscle  receives 
additional  branches  from  the  external  and  recurrent  larjmgeal  nerves. 

Tetanus  often  presents  its  first  symptom  as  spasm  of  those  muscles  of  masti- 
cation which  elevate  the  lower  jaw, — viz.,  the  masseter,  temporal  and  internal 
pterygoid  muscles, — and  of  the  eonstrii'tor  muscles  of  tlie  pharynx.  Consequently, 
the  patient  can  not  open  the  mouth,  and  deglutition,  or  swallowing,  is  difficult 
or  causes  choking  sensations.  Spasm  of  the  constrictor  muscles  of  the  pharynx 
and  difficult  deglutition  are  also  in'ominent  symptoms  of  hydrophobia. 

The  Pharyngeal  Plexus  of  Nerves  is  found  chiefly  upon  the  middle  con- 
strictor muscle.  It  is  formed  by  the  pharyngeal  branchi's  of  the  pneumogastric, 
external  laryngeal,  and  glosso-pharyngeal  nerves,  anil  of  the  superior  cervical 
sympathetic  ganglion.     It  supplies  the  muscular  and  other  coats  of  the  pharynx. 

The  Pterygo-maxillary  Ligament  is  a  fibrous  raphe  between  the  buccinator 
and  superior  constrictor  nuiscles,  and  extends  from  the  lower  extremity  of  the 
internal  jiterygoid  plate  to  the  jDOsterior  end  of  the  mylo-hyoid  ridge  or  internal 
oblique  line  of  the  lower  jaw. 

The  Pharyngeal  Aponeurosis,  the  fibrous  coat  of  the  i>harynx,  is  dense  and 
strong  where  the  muscular  coat  is  absent, — viz.,  at  the  sinuses  of  Morgagni  and  in 
the  triangular  intervals  between  the  origins  of  the  constrictor  muscles, — and  be- 
comes delicate  and  fades  away  below.  It  holds  tlie  pharynx  open  by  means  of  its 
attachment  to  the  I)asilar  process  of  the  occipital  bone,  the  cartilages  in  the 
middle  lacerated  foramina,  tlie  a])ices  of  the  j>cti'ous  portions  of  the  temjioral 
bones,  the  posterior  l)orders  of  the  internal  pterygoid  plates,  the  greater  cornua 
of  the  hyoid  bone,  and  the  ])osterior  Ijorders  of  the  alte  of  the  thyroid  cartilage. 


23-2  SURGICAL  ANATOMY. 

The  Mucous  Coat,  or  mucous  monibrane,  lining  the  jiharynx  is  continuous 
with  that  of  the  Eustaeliian  tubes,  nasal  cavities,  mouth,  larynx,  and  esophagus. 
It  contains  racemose  mucous  glands  and  scattered  lymphoid  follicles.  Because  of 
its  A'ascularity,  inflammation  of  this  membrane,  which  is  known  as  pharyngitis 
or  sore  throat,  frequently  occurs.  Through  the  continuity  of  the  mucous  mem- 
brane of  the  nose  and  larynx  the  catarrhal  process  may  extend  to  the  mucous 
membrane  of  those  cavities. 

Dissection. — Divide  the  posterior  wall  of  the  jiharynx  in  the  median  line, 
and  detach  it  from  the  base  of  the  skull  as  far  as  the  lateral  wall.  Tlion  turn  the 
two  flaps  outward,  to  study  the  interior  of  the  pharynx. 

Beneath  the  petrous  portion  of  the  temporal  bone  the  cavity  of  the  pharj'nx 
extends  outward,  forming  a  pouch — the  pharyngeal  recess. 

The  Pharyngeal  Tonsil  of  Luschka  is  a  collection  of  lymphoid  tissue  in  the 
posterior  wall  of  the  pharynx,  near  its  junction  with  the  roof 

The  Pharyngeal  Bursa  is  a  small  diverticulum  in  the  posterior  wall  of  the 
pharynx,  below  the  occipital  bone ;  it  is  most  conspicuous  in  the  fetus  and  in 
infants. 

Hypertrophy  of  the  Pharyngeal  Tonsil  is  the  source  of  adenoid  growths 
in  the  naso-pharynx.  Obstruction  of  the  i:)Osterior  narcs,  loss  of  nasal  resonance  in 
the  voice,  and  mouth  breathing  result.  Extension  of  the  hypertrophic  process 
into  the  Eustachian  tubes  causes  obstruction  of  those  tubes,  tinnitus  aurium,  or 
peculiar  sounds  in  the  ears,  and  deafnes.s. 

Post-pharyngeal  Abscess,  usually  resulting  from  caries  of  the  upper  cervical 
vertebrfe  or  suppuration  of  the  post-pharyngeal  lymphatic  gland,  may  bulge  into 
the  pharynx  and  cause  difficulty  in  deglutition  or  respiration.  Post-phaiyngeal 
abscesses,  and  those  arising  in  the  ptervgo-maxillary  region  and  temporal  fossa,  may 
rupture  into  the  pharynx. 

There  are  seven  Openings  into  the  pharynx  :  The  two  posterior  nares,  two 
Eustachian  tubes,  mouth,  larynx,  and  esophagus. 

The  two  posterior  nares  (choana?)  are  at  the  highest  point  of  the  anterior  wall 
of  the  pharynx.  They  are  separated  from  each  other  by  the  posterior  margin  of 
the  septum  of  the  nose.  Through  them  can  be  seen  the  middle  and  inferior  tur- 
binated bones.  When  a  mirror  is  placed  innnediatcly  behind  the  soft  palate,  tlie 
superior  turbinated  bones  can  also  be  seen. 

The  trumpet-shaped  orifices  of  the  Eustachian  tubes  iir(>  in  the  lateral  walls 
of  the  |)harynx,  at  about  the  level  of  the  ini'crior  liirliinateil  bones.  It  .should 
l)e  noticed  that  a  Eustachian  catheter  carried  through  the  inferior  meatus  to  the 
posterior  wall  of  the  piiarynx.  rotated  outwai'd,  and  di'awn  forward  along  the 
lateral  wall  of  the  jdiarynx  until  it  ])asses  over  the  elevation  at  the  posterior  mar- 


PLATE 


Pharyngeal  tonsil 


Pharyngeal  bursa 


Orifice  of  Eustachian  tube 


W'^'\' 


Posterior  wall  of  pharynx 


Lymphoid  nodules 


PHARYNGEAL  TONSIL  AND  BURSA. 
233 


PLATE 


Nasal  septum 
Posterior  naris 


Uvula 

Circumvallate  papillae 
Foramen  caecum 


Lymphoid  tissue  at 
base  of  tongus 


Cuneiform  cartilage 

Corniculum  laryngis 

Interarytenoid  fold 


^m^^s^m^ 


Middle  tuibinated  bene 


Inferior  turbinated  bone 


Inferior  constrictor  m 


Soft  palate 


Posterior  pillar  of  fauces 


Tonsil 


Epiglottis 


Aryteno-epiglottidean  fold 


^  Sinus  pyriformis 


Mucous  membrane  of  pharynx 
reflected  around  larynx 


Esophagus 


Trachea 


INTERIOR  OF  PHARYNX. 
236 


THE  rilARYSX.  237 

o-in  of  tlio  Eustachian  orifice,  will  readily  slip  into  the  Eustachian  tube  when 
puslied  backward  again.  Frdin  their  (iriliee.s  the  Eustachian  tubes  are  directed 
backward,  outward,  and  slightly  ujiwanl,  opening  into  the  tympanic  cavity  at  its 
anteri(_ir  wall.  The  inner  portion  of  the  Eu.-^taehiau  tube  is  cartilaginous  on  the 
up[)er  and  inner  sides,  and  llbrous  below.  The  outer  jxirtion  of  the  Eustachian 
tulu'  has  bony  walls,  and  begins  in  the  receding  angle  between  the  s(iuamous 
and  jietrous  portions  of  the  temporal  bone. 

The  isthmus  of  the  fauces,  or  posterior  opening  of  the  mouth,  is  situated  im- 
mediately below  the  posterior  nares  and  soft  palate.  Through  the  isthmus  some  of 
the  sli'uctures  of  the  mouth  can  be  examined  li'om  behind.  The  pillars  of  the 
fauces,  the  tonsils,  situated  in  the  recesses  of  the  fauces,  and  the  base  of  the  tongue 
are  more  satisfactorily  seen  through  the  isthmus  of  the  fauces  than  through  the 
buccal  orifice.  The  base  of  the  tongue  holds  a  vertical  position,  and  overhangs  the 
epiglottis.  Between  the  tongue  and  the  epiglottis  are  the  three  glosso-epiglottidcan 
folds  and  the  two  glosso-epiglottidean  pouches. 

The  superior  aperture  of  the  larynx  is  situated  l)elow  the  base  of  the  tongue. 
It  is  a  large,  triangular-shaped  opening,  its  wider  portion  being  directed  forward. 
It  slopes  oblicjuely  downward  and  backward  from  the  upper  extremity  of  the 
epiglottis.  It  is  bounded  in  front  by  the  epiglottis,  behind  by  the  interarytenoid 
fold  of  mucous  membrane,  and  on  each  side  by  the  aryteno-epiglottidean  fold 
and  the  tips  of  the  arytenoid  cartilages.  On  each  si<le  of  its  posterior  portion 
thei'e  is  a  deep  depression,  the  sbuis  pyrijormh,  in  which  foreign  bodies  may 
lodge. 

The  esophageal  opening  of  the  pharynx  is  the  narrowest  portion  of  the 
pharynx,  and  is  located  behind  tlie  lower  l:)order  of  the  cricoid  cartilage. 

Relations  of  the  Pharynx. — In  front  of  the  pharynx  are  the  posterior 
nares,  the  soft  palate,  the  istlnnus  of  the  fauces,  the  base  of  the  tongue,  the  hyoid 
bone,  and  the  larynx.  Behind  it  are  the  prevertebral  fascia,  the  post-pharyngeal 
lymphatic  gland,  the  rectus  capitis  anticus  major  and  longus  colli  muscles,  and  the 
bodies  of  the  upper  vertebra.  I^aterally,  its  upper  portion  is  in  relation  with  the 
Eustachian  tube,  the  inferior  maxillary  nerve,  the  styloid  process  of  the  temporal 
bone,  the  muscles  arising  from  that  process,  the  internal  pterygoid  muscles,  the 
parotid  gland,  the  glosso-pharyngeal,  pneumogastric,  spinal  accessory,  hypo-glossal, 
and  sympatlretic  nerves,  ascending  pharyngeal,  and  internal  carotid  arteries,  and  in- 
ternal jugular  vein  ;  its  lower  portion  is  in  relation  laterally  with  the  carotid  sheath 
and  its  contents,  the  lower  part  of  the  external  carotid  artery,  the  commencement 
of  the  superior  thyroid,  lingual,  and  facial  arteries,  the  lateral  lobe  of  the  thyroid 
body,  the  sterno-thyroid  muscle,  and  the  deep  cervical  chain  of  lymphatic  glands. 
Above  the  jiharynx  is  that  portion  of  the  base  of  the  skull  formed  by  the  body  of 


238  SUliGICAL  ANATOMY. 

the  sphenoid  bone  and  the  basilar  jirocess  of  the  occipital  bone.     Below,  it  leads 
into  the  esophagus. 

While  studying  the  relations  of  the  pharynx,  it  is  well  to  observe  some 
important  facts  associated  therewith.  The  l)ody  of  tlie  sphenoid  bone  and  the 
basilar  process  of  the  occipital  bone  and  the  upper  three  cervical  vertebrse  can. 
be  palpated  with  the  finger  inserted  into  the  pharynx.  The  anterior  arch  of 
the  atlas  is  in  the  same  transverse  i)lane  as  the  hard  palate ;  the  body  of  the 
axis  is  in  the  same  transverse  plane  as  the  cutting  edges  of  the  upper  teeth  ; 
and  the  body  of  the  tliird  cervical  vci'tebra  is  just  below  that  of  the  axis.  In 
necrosis  of  the  Ijod}'  of  the  sphenoid  bone,  basilar  process  of  the  occipital  bone, 
anterior  arch  of  the  atlas,  and  bodies  of  the  upper  cervical  vei'tebrse,  pus  and 
pieces  of  bone  may  be  discharged  through  the  pharjmx  and  mouth.  Sharj^ 
foreign  bodies  which  have  perforated  the  wall  of  the  jiharynx  may  wound  one 
of  the  carotid  arteries  or  the  internal  jugular  vein. 

Blood  Supply. — From  the  ascending  pharyngeal  artery,  the  tonsillar  and 
ascending  palatine  branches  of  the  fiicial  artery,  the  superior  laryngeal  branch  of 
the  superior  thyroid  artery,  and  the  inferior  laryngeal  branch  of  the  inferior 
thyroid  artery. 

Neeve  Supply. — From  the  pharyngeal  plexus  of  nerves. 
The  Veins  of  the  Pharynx  are  arranged  as  a  plexus  which  is  situated  between 
the  constrictor  muscles  and  the  prevertebral  fascia.     This  plexus  communicates 
above  with  the  pterygoid  plexus  of  veins,  and  empties  into  the  terminal  portion  of 
the  facial  vein  or  into  the  internal  jugular  vein. 

The  Lymphatic  Vessels  of  the  Upper  Portion  of  the  Pharynx  terminate  in 
the  post-pharyngeal  gland  ;  those  of  the  middle  portion,  in  the  superior  deep  cervi- 
cal glands ;  and  those  of  the  lower  portion,  in  the  inferior  deeji  cervical  lymphatic 
glands. 

The  Soft  Palate  is  a  musculo-membranous  and  freeh'  movable  curtain.  Its 
anterior  margin  is  attached  to  the  posterior  border  of  the  hard  palate  ;  its  posterior 
margin  is  free,  and  forms  the  upper  boundary  of  the  isthmus  of  the  fauces.  From 
the  center  of  this  curved  margin  the  uvula  is  susjiended.  The  lateral  margins  are 
attached  to  the  side  of  the  pharynx.  Its  upper  surface  is  convex  ;  its  lower,  con- 
cave. The  mucous  meml)rane  on  the  upper  surface  is  continuous  with  that  of  the 
floor  of  the  nasal  cavities,  and  the  mucous  membrane  of  its  lower  surface  with  that 
of  the  roof  of  the  mouth.  Between  its  two  layers  of  mucous  membrane  are  the  two 
levatores  palati,  two  ten.sores  jialati,  the  palato-pharyngeus,  jialato-glossus,  and 
azygos  uvulai  muscles,  an  aponeurosis,  glandulai  tissue,  vessels,  and  nerves.  The 
under  surface  of  the  soft  palate  contains  a  prominence  a  short  distance  behind  the 
last  molar  tooth.     Tiiis  elevation   is  produced  by  the  hamular  pi-ocess  of  the  in- 


PLATE 


Columna 

Ala  of  nose- 


Anterior  naris 


Anterior  pillar  of  fauces 
Recess  of  fauces 
Posterior  pillar  of  fauces 


Tongue  and  median  raphe- 


Hard  palate 


ANTERIOR  VIEW  OF  MOUTH. 
239 


•S—  11—16 


PLATE 


Palatine  aponeurosis 
Tensor  palati  tendon 


Levator  palati  m. 

Mucous  membrane 


Buccinator  m 
Pterygo-maxillary  ligament 
Harfiular  process  of  interna 
pterygoid  plate 
Palato-pharyngeus  m' 

Palato-glossus  m' 


_ower  jaw 

Palato-glossus  m, 
Inferior  fasciculus  of  palaro-pharyngeus  m. 
'Azygos  uvulae  m. 
'Tongue 
Pharynx 


MUSCLES  OF  SOFT  PALATE-ANTERIOR  VIEW. 
242 


PLATE  LVI. 


Tensor  palati  tendon 
Aponeurosis  of  soft  palate^  / 
Levator  palati  m.  ^ 

SJipingo-pharyngeus  m  ^  '' 


Tensor  palati   m. 
Eustachian  tube 

nternal  pterygoid  m. 


Palato-pharyngeus  m 

Tonsil  / 

Posterior  fasciculus  of 
palato-pharyngeus  nn 


Azygos  uvulae  m 


Palato-pharyngeus  m. 


•Mucous  membrane 


MUSCLES  OF  SOFT  PALATE, 
243 


THE  PIIARYXX.  245 

tei'nal  pterygoid  i)late  of  the  sphenoid  bone,  -wliieh  is  the  guide  in  divi<ling  thc^ 
aponeuroses  of  tlie  tensor  palati  und  levator  pahiti  muscles. 

Dissection. — Make  the  tissues  tense  by  means  of  hooks,  and  rclieet  the 
nuK'ous  mendirane  from  both  svu-faees  of  the  soft  jjalate  and  h'oni  the  pillars  of  the 
fauces.  Iveniove  the  nuicous  membrane  and  jiharyngeal  aponeui'osis  from  the 
upper  portion  of  the  side  of  the  pharynx,  in  order  to  fully  expose  the  levatores  and 
tensores  palati  nuiscles,  which  have  been  seen  during  the  dissection  of  the  su])erior 
constrictor  muscle  of  the  pliarynx. 

The  Levator  Palati  Muscle  arises  from  the  under  surface  of  the  petrous 
jiortion  of  the  temporal  bone,  in  front  of  the  carotid  canal  and  h-om  the  under 
and  inner  surfaces  of  the  cartilaginous  portion  of  the  Eustacliian  tube.  It  passes 
internal  to  the  upper  margin  of  tlie  superior  constrictor  muscle  of  the  jiharynx,  to 
reach  the  inner  surface  of  that  muscle,  and  is  inserted  into  the  palatine  aponeu- 
rosis and  into  its  fellow  of  the  opposite  side,  in  front  of  the  azygos  uvula?  muscle. 

AcTU)X. — It  elevates  the  soft  palate  and  brings  it  into  contact  with  the 
posterior  wall  of  the  i)harynx,  so  as  to  separate  the  naso-phar^-nx  from  the 
oro-pharynx  and  prevent  regurgitation  of  food  from  the  oro-pharynx  into  the  naso- 
l)harynx  and  nasal  cavities. 

The  Tensor  Palati  Muscle  arises  from  the  scaphoid  fossa,  which  is  situated 
behind  the  base  of  the  internal  pterygoid  plate,  from  the  sjjine  of  the  sphenoid 
bone,  and  the  outer  side  of  the  cartilaginous  portion  of  the  Eustachian  tube.  It 
is  a  flat  muscle,  which  lies  on  the  outer  surface  of  the  internal  pterygoid  jilate  and 
terminates  in  a  tendon  which  winds  around  the  hamular  process  of  that  plate. 
The  tendon  forms  almost  a  right  angle  with  the  muscle,  and  is  inserted  into  the 
palatine  aj^oneurosis,  with  which  it  is  continuous,  and  into  the  transverse  ridge  on 
the  under  surface  of  the  horizontal  plate  of  the  palate  bone.  A  bursa  facilitates 
the  movement  of  the  tendon  over  the  liamular  process. 

AcTiox. — It  renders  the  soft  palate  tense  and  opens  the  Eustachian  tube  dur- 
ing deglutition. 

The  Palato-pharyngeus  Muscle  is  situated  in  the  posterior  pillar  of  the 
fauces.  It  arises  from  the  soft  palate  by  two  slips,  which  are  separated  by  the 
levator  palati  and  azygos  uvulte'  muscles  and  are  continuous  with  the  correspond- 
ing slips  of  the  opposite  mu.scle,  and  also  has  an  origin  from  the  cartilage  of  the 
Eustachian  tul^e  (salpingo-pharyngeus).  It  passes  to  the  side  of  the  pharynx  and 
joins  the  stylo-pharyngeus  muscle,  to  be  inserted  into  the  j^osterior  border  of  the 
thyroid  cartilage  below  tlie  base  of  the  superior  coi-nu,  and  by  an  expansion  into 
the  pharj-ngeal  aponeurosis. 

Action. — It  elevates  the  pharynx  and  larynx  and  approximates  the  posterior 
pillars  of  the  fauces. 


246  SURGICAL  ANATOMY. 

The  Palato-glossus  Muscle  is  found  in  the  anterior  pilhir  of  tlie  fauces.  It 
arises  from  the  under  surface  of  tlie  palatine  aponeurosis,  and  is  partly  continuous 
with  the  palato-glossus  muscle  of  the  opposite  side  in  front  of  the  azygos  uvulae 
muscle.  It  is  inserted  into  the  side  of  the  tongue,  and  is  partly  continuous  with 
the  transverse  muscular  fibers  of  that  organ. 

Action. — It  draws  the  side  of  the  soft  palate  downward,  and  elevates  the 
sides  and  back  part  of  the  tongue,  thus  constricting  the  isthmus  of  the  fauces  to 
prevent  the  morsel  of  food  from  being  driven  back  into  the  mouth  in  deglutition. 

The  Azygos  Uvulae  Muscle  is  a  double  muscle,  and  arises  from  the  palatine 
aponeurosis  and  the  posterior  nasal  spine  on  the  liorizontal  plate  of  the  palate 
bone,  and  is  inserted  into  the  mucous  membrane  of  the  uvula. 

AcTiox. — It  elevates  and  shortens  the  uvula. 

The  Palatine  Aponeurosis  is  a  thin  but  den.se  fibrous  membrane,  which  is 
attached  to  the  ])Osterior  margin  of  the  hard  palate  and  gradually  disappears  as  it 
approaches  the  posterior  or  free  border  of  the  soft  palate.  Latei'ally,  it  is  continu- 
ous with  the  pharyngeal  aponeurosis.  It  receives  the  tendinous  expansion  of  the 
tensor  palati  muscle,  and  gives  form  to  the  soft  palate. 

The  glandular  tissue  of  the  soft  palate  is  most  al>undant  in  its  upper  surface, 
although  there  is  some  adenoid  tissue  in  its  under  surface. 

Blood  Supply. — From  the  dorsalis  lingure  and  the  ascending  pharyngeal 
artery,  the  ascending  palatine  branch  of  the  facial  arterj',  and  the  jjosterior  pala- 
tine branch  of  the  internal  maxillary  artery. 

The  veins  correspond  to  the  arteries.  The  lymphatics  empty  into  the  glands  at 
the  angle  of  the  jaw. 

Nerve  Supply. — From  Meckel's  ganglion,  the  glosso-pharyngeal  nerve,  the 
pharyngeal  plexus  of  nerves,  and  the  otic  ganglion.  The  tensor  palati  muscle  is 
supplied  by  a  branch  from  the  otic  ganglion.  The  levator  palati,  palato-glossus, 
palato-pharyngeus,  and  azygos  uvuhc  muscles  are  i)robab]y  supplied  by  branches 
from  the  pharyngeal  plexus,  which  are  derived  from  the  spinal  accessory  nerve. 

Clefts  of  the  Soft  Palate  may  exist  independently  of  clefts  of  the  hard 
palate.  They  are  widened  by  the  tensor  palati,  levator  palati,  palato-glossus, 
and  palato-pharyngeus  muscles.  These  clefts  give  rise  to  difficulty  in  deglutition, 
because  they  allow  food  to  pass  into  the  naso-pliarynx  and  nose.  Before  closing 
the  cleft,  the  aponeuroses  of  these  muscles  are  divided  to  ])revent  them  from  caus- 
ing tension  \x\)(m  the  sutures.  The  aponeuroses  of  the  tensor  palati  and  levator 
palati  muscles  may  be  divided  by  one  incision.  A  slender  bistoury,  with  its 
cutting  edge  directed  forward  and  upward,  is  inserted  into  the  soft  palate  slightly 
in  front  of  and  close'  to  tlie  inner  side  of  the  liannilar  ]irocess  of  the  internal 
Ijterygoid  jilate  of  the  sphenoid  bone,  until  it  projects  through  the  superior  surface 


TUK   LAUYSX.  247 

of  tlie  soft  palate.  As  the  knife  is  pushed  iiiiwanl  it  cuts  the  tensor  palati  aponeu- 
rosis. The  bistoury  is  thru  carried  upward,  ibrwanl,  and  inward,  cutting  the 
superior  surface  of  tiie  sott  palate  for  a  distance  sufficient  to  allow  severance  of  the 
levator  pahiti  aponeurosis.  The  palato-glossus  and  |iahito-pharvngeus  muscles  can 
he  divided  1)V  a  shallow  incision  across  each  of  the  pillars  of  the  fauces.  Tiie 
attachment  of  the  palatine  aponeurosis  to  the  posterior  margin  of  the  hard  palate 
may  also  cause  dilficulty  in  aiiproximating  the  freshened  margins  of  tlie  cleft,  and 
should  be  divided  as  far  as  neees,sary.  The  success  of  the  operation  depends 
chiefly  upon  the  relief  of  tension  upon  the  sutures. 

Paralysis  of  the  Muscles  of  the  Soft  Palate  and  Pharynx  may  occur 
during  convalescence  from  diphtheria.  As  a  result,  tiiere  is  dilHculty  in 
swallowing  and  regurgitation  of  food  through  the  nose. 


THE  LARYNX. 


The  larynx  is  a  membrano-cartilaginous,  box-like  organ.  It  is  the  organ  of 
voice,  assists  in  protecting  the  respiratory  tract  from  the  entrance  of  foreign  bodies 
during  deglutition,  and  closes  the  respiratory  tract,  so  that  the  chest  can  be  made 
firm  tluring  gi'eat  muscular  effort.  It  is  situated  at  the  upper  portion  of  tlie 
respiratory  tract,  above  the  trachea  and  in  front  of  the  lower  jiortion  of  the  pharynx. 
Anteriorly,  it  is  covered  1)}'  skin,  superficial  and  deep  fascia;,  two  thin  layers  of 
muscular  tissue,  and,  occasionally,  a  jsrocess  of  the  middle  lobe  of  the  thyroid 
gland.  The  superficial  stratum  of  muscular  tissue  is  composed  of  the  sterno- 
Iryoid  and  omo-hyoid  muscles ;  the  deep  stratum,  of  the  sterno-thyroid  and  tlij-ro- 
hyoid  muscles.  The  great  vessels  lie  on  each  side  of  the  larynx  in  the  groove 
between  the  larynx  and  the  sterno-mastoid  muscle.  It  is  suspended  from  the  skull 
by  the  stylo-hyoid  ligament,  the  muscles  attached  to  the  superior  surface  of  the 
hyoid  bone,  and  the  stylo-pharvngeus  and  palato-pharyngeus  nniscles,  which  are 
inserted  into  the  posterior  borders  of  the  alse  of  the  thyroid  cartilage.  It  is  lined 
internally  by  mucous  membrane  which  is  continuous  above  with  that  lining  the 
pharynx,  and  below  with  that  of  the  trachea.  It  consists  of  three  single  cartilages 
and  three  i)airs  of  cartilages  united  by  membranes,  ligaments,  and  muscles.  The 
three  single  cartilages  are  the  thyroid,  cricoid,  and  epiglottis ;  the  paired  ones  are 
the  arytenoid,  cornicula  laryngis,  and  cuneiform.  The  larynx  is  larger  in  all  its 
dimensions  in  the  male  than  in  tlie  female. 

The  Superior  Aperture  of  the  Larynx  inclines  obli(|uely  downward  and 
backward.     It  is  bounded  in  front  by  the  epiglottis;  fiehind,  by  the  interarj'tenoid 


248  SURGICAL   ANATOMY. 

fold  of  mucous  membrane ;  and  at  the  sides,  by  the  aryteno-epiglottidean  folds 
and  the  tips  of  the  arytenoid  cartilages. 

The  aryteno-epiglottidean  folds  extend  from  the  sides  of  the  epiglottis  to  the 
summits  of  the  arytenoid  cartilages.  They  are  composed  of  two  layers  of  mucous 
membrane,  between  which  are  a  snpi)()rting  layer  of  connective  tissue  ;  the  cor- 
nicula  laryngis,  which  rest  upon  the  summits  of  the  arytenoid  cartilages ;  the  cunei- 
form cartilages,  which  lie  in  front  of  the  arytenoid  cartilages ;  and  the  aryteno- 
epiglottidean  mu.scles.  In  viewing  the  larynx  from  above,  the  corniculum  laryngis 
and  cuneiform  cartilage  appear  as  two  small  swellings  in  the  ar^yteno-epiglottidean 
fold.  In  these  folds  there  is  much  loose  sul>nuieous  tissue,  which  is  the  chief  site 
of  the  swelling  in  edema  of  the  larynx.  Tliis  swelling  may  be  so  extensive  as  to 
interfere  seriously  with  the  entrance  of  air  into  tlie  larynx,  and  laryngotomy, 
tracheotomy,  or  intuliation  may  become  neces.sar3'. 

The  sinus  pyriformis,  which  is  between  the  aryteno-c]iiglottidean  fold  and 
tlie  ala  of  the  thyroid  cartilage,  the  three  glosso-epiglottidean  folds,  and  the 
valleculee,  between  the  epiglottis  and  the  base  of  tlie  tongue,  have  been  previously 
described. 

Two  pairs  of  folds  may  be  seen  stretching  across  the  cavity  of  the  larynx. 
The  upper  pair  is  formed  by  the  false  vocal  cords,  and  the  lower  pair  by  the  true 
cords,  which  are  more  closely  approximated.  A  depression — the  ventricle  of  the 
larynx — exists  between  the  true  and  false  cords.  The  interval  between  the  true 
vocal  cords  is  the  chink  of  the  glottis,  or  rima  glottidis.  The  true  vocal  cords 
divide  the  larynx  into  a  supra-i'imal  and  an  infra-rinial  jiortion. 

The  Supra-rimal  Portion  of  the  larynx  extends  from  the  superior  aperture  to 
the  true  vocal  cords.     It  is  wide  and  triangular  aliove,  and  becomes  narrow  below. 

The  Infra-rimal  Portion  is  compre.s.sed  laterally  above,  and  becomes  circular 
below,  where  it  is  surrounded  by  the  cricoid  cartilage  and  leads  into  the  trachea. 
In  laryngotomy  the  knife  enters  this  portion  of  the  larynx  and  is  directed  down- 
ward and  backward  to  avoid  the  vocal  cords. 

Dissection. — Clean  the  anterior  portion  of  the  external  surface  of  the  larynx, 
entirely  removing  the  attachments  of  the  sterno-hyoid,  omo-hyoid,  and  th}-ro- 
hyoid  muscles  from  the  hyoid  bone,  those  of  the  thyro-hyoid  and  sterno-thyroid 
muscles  from  the  thyroid  cartilage,  and  the  attachments  of  the  inferior  constrictor 
muscles  of  tlic  jiharynx  froni  the  thyroid  and  cricoid  cartilages.  ■  Avuid  injuring 
the  su|icri(ir  laryngeal  artery  and  tlie  internal  liranch  of  the  superinr  laryngeal 
nerve,  which  pierce  the  thyro-hyoid  membrane  ;  the  externa!  laryngeal  nerve, 
whicli  sup]ilies  the  inferior  constrictor  and  the  crico-thyroid  muscle  ;  the  crico- 
thyroid artery,  which  crosses  the  crico-thyroid  membrane ;  and  tlie  recurrent 
laryngeal  nerve  and  inferior  laryngeal  artery,  which   i)ass  to  the   larynx  behind 


PLATE  LVI! 


Vocal  process  of  arytenoid  cartilage 
True  vocal  cord 
Sinus  pyriformis 


Interarytenoid  fold 

Posterior  wall  of  pharynx 

Corniculum  laryngis 

Cuneiforna  cartilage 

Aryteno-eplglottidean  fold 


False  vocal  cord 
Ventricle  of  larynx 


Posterior  pillar 
of  fauces 


Tonsil 
Anterior  pillar  of  fauces 


Lateral  glosso-epio-lottidean 
fold  '^^ 


Median  glosso-epiglottidean 
fold 


Adenoid  tissue  at 
base  of  tongue 


Foramen  caecum 


Circumvallate  papillae 
Fungiform  papillae 


SUPERIOR  APERIURE  OF  LARYNX. 
250 


PLATE  LVIIl 


Greater  cornu  of  hyoid  bo 

Lesser  cornu  of  hyoid  bo 
Lateral  portion  of  tliyro-hyoid  membran 

Internal  laryngeal 
Superior  laryngeal  a 


Thyroid  cartilage 


Crico-thyroid  membran 
Crico-thyroid  m. 

Lateral  lobe  of  thyroid  gland 
Trachea 

Isthmus  of  thyroid  gland 


Epiglottis 


Hyoid  bone 

ntral  portion  of  thyro-hyoid 
embrane 


Inferior  constrictor  m. 
of  pharynx 


Superior  thyroid  a. 

rico-thyroid  a. 

evatop  glandulae  thyroidcae 
1. 

ricoid  cartilage 


thyroid  veins 


LARYNX  AND  CRICO-THYROID  MUSCLE. 
251 


PLATE  LIX, 


Epiglottis 


Cartilage  tri+icea 


Internal  laryngeal  branch  of   superior  laryngeal  n 
Superior  laryngeal  a 


Superior  cornu  of  thyroid  cartil. 


Ala  of  thyroid  cartilage 


Oblique  line  of  thyroid  cartilage 

Inferior  border  of  thyroid  cartilage 
Inferior  cornu  of  ihyroid  cartilage 

Cricoid  cartilage 

Recurrent  laryngeal  n 


Greater  cornu  of  hyoid  bone 
Thyro  hyoid  ligament 
Lesser  cornu  of  hyoid  bone 

Body  of  hyoid  bone 

Lateral  portion  of  thyro  hyo'd  mcnr.brane 

Central  portion  of  thyro-hyoid  membrane 

Superior  border  of  thyroid  cariilage 
tncisura  thyroideae 


Angle  of  thyroid  cartilage 


.  Lateral  portion  of  crico-thyro.d  membrane 
Central  portion  of  crico-thyroid  membrane 
Capsular  ligament  of  crico-thyroid  articulation 


ANTERIOR  VIEW  OF  LARYNX,  INCLUDING  CRICO-THYROID  MEMBRANES. 

254 


THE  LAh'VXX.  255 

the  cric'O-thyrditl  articulation.  This  disHectioii  more  thorouglily  exposes  tlie  tliyro- 
liyoid  iiu'iiihraiu',  thyroid  c-artihigv,  crieo-tliyroid  muscles,  crico-thyroid  momliranc, 
and  cricoid  cartilajic 

The  Thyro-hyoid  Membrane,  which  is  lart>cly  coniposcd  of  clastic  lihcrs, 
extends  tVnni  the  u|i|i(.t  Imnli  r  oi'  the  thyiciid  carlila^c  to  (lie  posterior  sujicrior 
border  of  the  hyoid  ixiiic.  Its  central  purtion  is  thick  and  strong,  and  its  lateral 
portions  are  thin  and  pierced  by  the  supt'rior  laryngeal  arteries  and  internal 
laryngeal  nerves  on  their  way  to  the  interior  of  the  larynx.  The  thyro-hyoid 
bursa  intervenes  between  the  thyro-hyoid  membrane  and  the  posterior  surftice  of 
the  liyoid  bone,  and  may  be  enlarged  an<l  produce  u  cystic  tumor  and  swelling  in 
the  median  line  of  the  neck.  Laterally,  the  thyro-hyi)id  nienil)rane  is  continuous 
with  the  thyro-hyoid  ligaments.  Behind  the  tln'ro-hyoid  membrane  lies  the 
epiglottis,  from  which  it  is  sejiarated  by  a  small  amount  of  loose  areolar  tissue. 

The  Thyro-hyoid  Ligaments  are  clastic  bands  connecting  the  superior 
cornua  of  the  thyroid  cartilage  with  the  tii)s  of  the  greater  cornua  of  the  hyoid 
bone.  They  frequently  contain  a  nodule  of  cartilage  (cartilago  triticea),  which 
may  be  ossified. 

The  thyroid  and  cricoid  cartilages  will  be  described  later. 

The  Crico-thyroid  Muscle  arises  from  the  anterior  portion  of  the  side  of  the 
cricoid  cartilage,  and  is  inserted  into  the  anterior  border  of  the  inferior  cornu  and 
the  outer  surface  of  the  lower  border  of  the  ala  of  the  thyroid  cartilage.  Its  upper 
fibers  pass  obli(iuely  upwaivl  and  backward,  and  its  lower  fibers  horizontally 
backward.  At  its  insertion  it  lilends  with  the  origin  of  the  inferior  constrictor 
muscle  of  the  jiharynx.  It  rests  upon  the  cricoid  cartilage  and  lateral  portion  of 
the  crico-thyroid  membrane.  In  the  interval  between  the  two  crico-thyroid 
muscles  the  central  portion  of  the  crico-thyroid  membrane  is  seen. 

Nerve  Supply. — From  the  external  laryngeal  branch  of  the  superior  laryn- 
geal nerve. 

Action. — It  depresses  the  anterior  portion  of  the  thyroid  cartilage,  thus  mak- 
ing the  vocal  cords  tense. 

Dissection. — Remove  the  crico-thyroid  muscle  on  one  side,  in  order  to  more 
fully  expose  the  crico-thyroid  membrane. 

The  Crico-thyroid  Membrane  is  chiefly  composed  of  elastic  fdwrs.  It  is 
divided  into  a  central  and  two  lateral  portions,  which  are  lined  by  the  mucous 
membrane  of  the  larynx.  The  central  portion  is  thicker  and  stronger  than  the 
lateral  portions,  and  extends  from  the  middle  of  the  upper  border  of  the  anterior 
portion  of  the  cricoid  cartilage  to  the  corresponding  portion  of  the  lower  border  of 
the  thyroid  cartilage.  Near  the  lower  border  of  the  thyroid  cartilage  it  is  crossed 
by  the  anastomosing  crico-thyroid  branches  of  the  sujicrior  thyroid  arteries,  and  is 


256  SURGICAL   ANATOMY. 

pierced  by  one  or  two  branches  of  the  arch  formed  by  the  crico-thj^roid  arteries. 
It  lies  immediately  beneath  the  interval  between  the  two  sterno-hyoid  muscles 
and  between  the  two  sterno-thyroid  muscles,  and  may  be  seen  in  the  triangular 
interval  between  the  inner  margins  of  the  crico-thyroid  muscles.  Laryngotomy  is 
performed  through  the  lower  Ijorder  of  this  portion  of  the  membrane. 

The  lateral  portions  of  the  membrane  are  thin,  and  pass  upward  from  the 
inner  margin  of  the  upper  border  of  the  cricoid  cartilage  to  become  continuous 
with  the  true  vocal  cords.  The  latei-al  portions  of  the  crico-thyroid  membrane  are 
covered  by  the  crico-thyroid,  lateral  crico-arytenoid,  and  thyro-arytenoid  muscles. 

Dissection. — Place  the  larynx,  with  the  anterior  aspect  down,  upon  a  board, 
and  fasten  it  in  that  position  with  pins  or  tacks.  Carefully  remove  the  pharyngeal 
mucous  membrane  from  its  posterior  aspect,  preserving  the  recurrent  laryngeal 
nerve  and  the  inferior  laryngeal  artery,  which  is  a  branch  of  the  inferior  thyroid 
artery.  Then  remove  the  mucous  membrane  from  the  external  surface  of  the 
aryteno-epiglottidean  fold  and  the  portion  of  the  thyroid  cartilage  bounding  the 
sinus  pyriformis.  Next  cut  through  the  crico-thyroid  articulation  on  one  side,  and 
divide  the  ala  of  the  thyroid  cartilage  about  one-fourth  of  an  inch  to  the  same 
side  of  the  angle  of  that  cartilage.  This  dissection  requires  care  to  avoid  injuring 
the  underlying  muscles,  vocal  cords,  lateral  portion  of  the  crico-thyroid  membrane, 
the  superior  laryngeal  artery,  the  internal  laryngeal  nerve,  and  the  terminal  por- 
tion of  the  recurrent  laryngeal  nerve  and  inferior  laryngeal  artery. 

The  Crico-arytenoideus  Posticus  Muscle  arises  from  the  surface  at  the  side 
of  the  posterior  median  ridge  of  the  cricoid  cartilage.  It  is  inserted  into  the  pos- 
terior portion  of  the  external  angle  (muscular  process)  of  the  arytenoid  cartilage. 
Its  upper  libers  pass  transversely  outward  ;  its  middle  fibers,  obliquely  upward  and 
outward,  and  its  lower  fibers,  vertically  upward. 

Nerve  Supply. — From  the  recurrent  laryngeal  nerve. 

Action. — It  rotates  the  arytenoid  cartilage,  and  opens  the  rima  glottidis,  and 
its  vertical  fibers  produce  the  gliding  motion  of  that  cartilage. 

The  arytenoideus  muscle  is  a  single  muscle,  situated  between  the  arytenoid 
cartilages.  It  consists  of  superficial  oblique  fibers  and  a  transverse  portion.  The 
ol)]i(iue  fibers  arise  from  the  external  angle  of  one  arytenoid  cartilage,  and  pass 
upwar<l  and  outward  to  the  summit  of  tlic  op|)osite  arytenoid  cartilage,  crossing 
the  (ilili(iuc  fibers  from  the  other  side  in  tlic  form  of  the  letter  X.  Some  of  these 
fil>ers  ]iass  around  the  apex  of  tlie  arytenoid  cartilage,  and  join  the  aryteno- 
epiglottideus  muscle  to  form  a  sphincter  for  the  superior  aperture  of  the  larynx. 
The  transverse  portion  is  thicker,  and  connects  the  posterior  concave  surfaces  of 
the  arytenoid  cartilages. 

Nerve  Supply. — From  the  recurrent  and  sujierior  laryngeal  nerves. 


11—17 


PLATE  LX, 


Laryngeal  surface  of  epiglottis 


Muscular  process  of  arytenoid  cartilage 


Cricoid  cartilage 


Arytenoepiglottidean  fold 
Aryteno-epiglottideus  m. 

Arytenoideus  m. 
■Thyroid  cartilage 


Crico-arytenoideus  posticus  m. 


1 


Recurrent  laryngeal  n. 


I 


MUSCLES  OF  LARYNX-POSTERIOR  VIEW. 
23S 


PLATE  LXl. 


Epiglottis- 


Aryteno-epiglottidean  fold- 
Aryteno-epiglottideus  m. — 


Thyro-epiglottideus  m.- 


Thyroid  cartilage 

Thyro-arytenoideus  m: 

Crico-thyrold  membrane- 
Cf'coid  cartilage 


Superior  cornu  of  thyroid  cartilage 


Arytenoideous  m. 
Muscular  process  of  arytenoid  cartilag 


Crico-arytenoideus  lateralis  m. 
Crico-atyleno'deus  posticus  m. 


Facet  for  articulation  with  inferior  cornu  of  thyroid  cartilage 


MUSCLES  OF  LARYNX-LATERAL  VIEW. 
259 


THE  LARYXX.  2(11 

Action. — The  arvtenoideus  muscle  draws  the  arytenoid  cartilages  together 
and  approximates  the  vocal  cords. 

The  Crico-arytenoideus  Lateralis  Muscle  arises  from  the  upper  border  of  the 
cricoid  cartihige,  in  liunl  of  the  crieo-urytenoid  articulation.  It  is  inserted  into 
the  anterior  and  inferior  aspects  of  the  external  angle  of  the  arytenoid  cartilage. 
It  is  covered  by  tlie  tiiyroid  cartilage  and  the  crico-thyroid  muscle,  and  rests  upctn 
the  lateral  portidu  of  the  crico-thyroid  nienil)rane.  Its  upper  border,  near  its 
termination,  blends  with  the  thyro-arytenoid  muscle. 

Nerve  Supply. — From  the  recurrent  laryngeal  nerve. 

Action. — It  pulls  the  arytenoid  cartilage  forward,  relaxing  the  vocal  cords, 
and  rotates  that  cartilage  inward,  approximating  the  cords  and  closing  the  rima 
glottidis. 

The  Thyro-arylenoideus  Muscle  is  a  quadrilateral  band  of  muscular  fillers 
which  is  divided  into  a  superior  and  an  inferior  portion.  The  superior  portion 
is  broad  and  thin,  and  is  situated  above  the  level  of  the  A'ocal  cords,  external  to 
the  ventricle  of  the  larynx  and  the  laryngeal  pouch.  It  arises  from  the  lower  two- 
thirds  of  the  inner  surface  of  the  ala,  near  the  angle  of  the  thyroid  cartilage,  and 
is  inserted  into  the  anterior  surface  and  external  angle  of  the  arytenoid  cartilage. 
The  inferior  portion  is  closely  attached  to  the  true  vocal  cord.  It  arises  from  the 
ala,  near  the  angle  of  the  thyroid  cartilage,  external  to  the  attachment  of  the 
true  vocal  cord,  and  is  inserted  into  the  anterior  angle  (\'ocal  process)  and  the 
adjacent  portion  of  the  anterior  surface  of  the  arytenoid  cartilage.  Some  of  its 
deeper  fibers  {ary^^ocalis  of  Ludwig)  are  attached  to  the  vocal  cord  at  several  points. 

Nerve  Supply. — From  the  recurrent  laryngeal  nerve. 

Action. — The  thyro-arytenoid  muscles  relax  the  true  vocal  cords  by  drawing 
the  arytenoid  cartilages  forward,  and  approximate  them  by  drawing  the  vocal 
processes  downward  and  inward.  The  ary-vocalis  can  make  a  portion  of  the 
true  cord  tense  while  the  remainder  is  relaxed. 

The  Thyro-epiglottideus  Muscle  is  composed  of  a  few  of  the  uppermost  fibers 
of  the  thyro-arytenoideus  muscle,  which  turn  upward,  external  to  the  laryngeal 
pouch,  to  be  attached  to  the  side  of  the  epiglottis. 

Nerve  Supply. — From  the  recurrent  laryngeal  nerve. 

Action. — It  depresses  the  epiglottis. 

The  Aryteno-epiglottideus  Muscle  is  situated  in  the  aryteno-epiglottidean 
fold.  It  arises  from  the  apex  and  anterior  border  of  the  arytenoid  cartilage,  above 
the  false  vocal  cord.  Its  upper  fibers  are  inserted  into  the  mucous  membrane  at 
the  margin  of  the  aryteno-epiglottidean  fold,  and  its  lower  fibers  are  inserted  into 
the  side  of  the  epiglottis.  It  is  joined  by  .some  of  the  fibers  of  the  oblique  portion 
of  the  arj-tenoideus  muscle,  which  pass  around  the  apex  of  the  arytenoid  cartilage. 


262  SURGICAL   ANATOiMY. 

Nerve  Supply. — From  the  recurrent  laryngeal  nerve. 

Action. — It  pulls  the  epiglottis  backward  and  compresses  the  laryngeal 
pouch,  and  with  the  assistance  of  the  arytenoideus  muscle  acts  as  a  sphincter  of 
the  .superior  apei'ture  of  the  larynx. 

The  muscles  just  described — viz.,  the  two  crico-thyroidei,  two  crico-arytenoidei 
postici,  one  arytenoideus,  two  crico-arytenoidei  laterales,  two  thyro-arytenoidei,  two 
thyro-epiglottidei,  and  two  aryteno-epiglottidei — are  the  intrinsic  muscles  of  the 
larynx. 

The  extrinsic  muscles  of  the  larynx — viz.,  the  sterno-thyroid,  thyro-hyoid, 
stylo-pharyngei,  and  palato-pliar^'ngei — have  been  described  with  the  neck  and 
pharynx.  These  muscles  are  assisted  by  all  the  muscles  which  elevate  or  depress 
the  hyoid  bone  and  larynx  or  hold  the  hyoid  bone  firm. 

In' Laryngismus  Stridulus,  or  laryngeal  asthma,  there  occurs  spasm  of  the 
muscles  of  the  larynx.  This  condition  occurs  most  frecj[uently  in  children,  is 
usually  due  to  reflected  irritation,  as  after  eating  indigestible  food,  and  ma}"-  be 
caused  by  irritation  of  the  nerve  centers  in  the  medulla  oblongata.  In  adults  it 
may  be  caused  by  pressure  upon  the  recurrent  laryngeal  nerve  by  aneurysms, 
malignant  growths  of  the  esophagus  or  posterior  mediastinal  glands,  or  enlarge- 
ment of  the  thyroid  body.  It  may  also  l)e  produced  liy  irritation  from  foreign 
bodies  in  the  larynx  or  lower  part  of  the  pharynx. 

Nerve  Supply  of  the  Larynx. — From  the  superior  laryngeal  and  recurrent 
laryngeal  branches  of  the  pneumogastric  nerve. 

The  Superior  Laryngeal  Nerve  divides  into  the  external  and  internal  laryn- 
geal nerves.  The  external  laryngeal  nerve  passes  downward  with  the  superior 
thyroid  artery,  and  sup[)lies  the  crico-thyroid  muscle.  The  internal  laryngeal 
nerve  pierces  the  thyro-hyoid  membrane  with  the  superior  laryngeal  artery,  passes 
downward  and  backward,  ramifies  upon  the  intrinsic  muscles  in  the  lateral  wall 
of  the  larynx,  and  supplies  the  mucous  membrane,  sending  a  branch  to  the  ary- 
tenoideus muscle.  The  internal  laryngeal  nerve  is  the  sensory  nerve  of  the 
larynx. 

The  Recurrent  Laryngeal  Nerve  is  the  motor  nerve  of  the  larynx,  and  reaches 
it  behind  the  crico-thyroid  articulation,  where  it  divides  into  an  anterior  and  a 
posterior  branch.  The  posterioi-  branch  supplies  the  arytenoideus  muscle  and  the 
crico-arytenoideus  posticus  muscle,  and  communicates  with  the  internal  laryngeal 
bi'ancli  of  the  superior  laryngeal  nerve  ;  the  anterior  branch  sui)})lies  all  the 
other  intrinsic  mu.scles  except  the  crico-thyroid  muscle. 

Paralysis  of  the  Right  Side  of  the  Larynx  may  be  caused  by  pressure  upon 
the  right  recurrent  laryngeal  nerve,  i)roduced  by  aneury.sm  of  the  first  portion  of 
the  right  subclavian  artery  or  lower  portion  of  the  right  common  carotid  artery. 


PLATE  LXII. 


IGreater  cornu  of  hyoid  bone. 
Thyro-hyold  ligament 


IThyro-hyoid  membrane. 


^Superior  cornu  of  thyroid  cartilage 
I Aryteno-epiglottideus  m. 


Arytenoideus  m. 

Posterior  border  of  thyroid  cartilage 

Posterior  crico-arytenoid  m. 


Crico-thyroid  articulation- 


Cartilago  trlticea 


Internal  laryngeal  n. 
Superior  laryngeal  a. 


Cricoid  cartilage 

Recurrent  laryngeal  n. 
Inferior  laryngeal  a. 


NERVES  AND  ARTERIES  OF  LARYNX. 
263 


II 


4* 


•* 


THE  LARYNX.  '2G5 

enlargement  of  tlie  tliyinid  Ixxly,  malignant  disease  of  the  esophagus,  and  cicatrices 
at  the  api'X  '■'(  tlie  rii;iit  iilcura,  as  in  phllii.sis. 

Paralysis  of  the  Left  Side  of  the  Larynx  may  be  caused  by  pressure  upon 
till'  left  recurrent  laryngeal  nerve,  produced  by  aneurysm  of  the  arch  of  the  aorta 
and  lower  porti<in  of  the  left  common  carotid  artery,  malignant  disease  of  the 
esophagus,  and  enlargement  of  the  thyroid  body.  The  left  side  of  the  larynx  is 
more  frequently  paralyzed  than  the  right;  this  is  explained  liy  the  longer  course 
of  the  left  recurrent  laryngeal  nerve,  and  by  its  relation  with  the  arch  of  the  aorta, 
which  is  more  commonly  affected  by  aneurysm  than  the  first  portion  of  the  right 
subclavian  artery.  Moderate  pressure  uj^on  one  of  the  recurrent  laryngeal  nerves 
causes  spasm  of  the  nniscles  of  one  side  of  the  larynx,  dyspnea,  and  change  of 
voice;  greater  pressure  causes  paralysis  and  change  of  voice.  Both  nerves  may  be 
paralyzed  by  a  lesion  of  the  medulla  oblongata,  as  in  labio-glosso-pharyngeal  par- 
alysis or  disseminated  sclerosis,  or  by  pressure  from  a  goiter  or  malignant  growth 
of  the  esophagus.  In  bilateral  paralysis  the  true  vocal  cords  are  immovable,  and 
the  rima  glottidis  is  in  the  position-  assumed  in  quiet  breathing. 

Blood  Supply  of  the  Larynx. — From  the  superior  laryngeal  and  inferior 
larj'ngeal  arteries,  and  some  twigs  from  the  dorsalis  linguaj  artery,  which  supply 
the  ei)iglottis. 

The  Superior  Laryngeal  Artery  is  a  branch  of  the  superior  thyroid  artery, 
and  pierces  the  thyro-hyoid  memljrane  with  the  internal  laryngeal  nerve.  It  runs 
downward  and  backward  with  that  nerve  to  anastomose  with  the  inferior  laryngeal 
artery. 

The  Inferior  Laryngeal  Artery  is  derived  from  the  inferior  thyroid  artery, 
and  accompanies  the  terminal  portion  of  the  recurrent  laryngeal  nerve. 

The  Veins  of  the  Larynx. — The  superior  laryngeal  veins  empty  into  the 
superior  thyroid  veins,  and  the  inferior  laryngeal  veins  into  the  inferior  thyroid 
veins. 

The  Lymphatic  Vessels  of  the  Larynx  terminate  in  the  deep  cervical  chain 
of  lymphatic  glands.  The  lymphatics  from  the  upper  or  supra-rimal  jiortion  of 
the  larynx  pass  through  the  thyro-hyoid  membrane  with  the  superior  laryngeal 
vessels,  and  join  the  superior  set  of  deep  cervical  glands  near  the  bifurcation  of 
the  common  carotid  artery.  The  lymphatics  from  the  lower  or  infra-rimal  portion 
of  the  larynx  pierce  the  crico-thyroid  membrane,  join  the  prelaryngeal  gland  situ- 
ated upon  that  membrane,  and  pass  thence  to  some  lateral  laryngeal  glands  situ- 
ated between  the  lower  ])ortion  of  the  larynx  and  the  lateral  lobes  of  the  thyroid 
body.  The  efferent  vessels  from  the  lateral  or  inferior  laryngeal  glands  terminate 
in  the  inferior  set  of  deep  cervical  glands. 

Dissection. — Remove  the  muscles  from  one  side  of    the    larynx — viz.,  the 


266  SURGICAL   ANATOMY. 

lateral  crico-thyroid,  thyro-arytenoid,  thyro-epiglottideus,  and  aryteno-epiglottideus 
muscles.  Next  cut  away  the  mucous  membrane  and  connective  tissue  from  the 
same  side,  from  the  upper  border  of  the  true  vocal  cord  to  the  upper  margin  of 
the  aryteno-epiglottidean  fold,  preserving  intact  the  cuneiform  cartilage  which  lies 
in  that  fold.  The  lateral  portion  of  the  crico-thyroid  membrane,  both  true  vocal 
cords,  and  one  side  of  the  interior  of  the  laryn.x  are  exposed  by  this  procedure. 

The  True  or  Inferior  Vocal  Cords,  or  inferior  thyro-arytenoid  ligaments,  are 
two  pearly  white,  tibro-elastic  bands  stretching  between  the  anterior  angles  (vocal 
processes)  of  the  arytenoid  cartilages  and  the  retiring  angle  of  the  thyroid  cartilage 
on  each  side  of  the  median  line.  They  are  continuous  with  the  lateral  portions 
of  the  crico-thyroid  membrane,  and  on  transverse  section  are  prismatic  in  form. 
The  free  border  is  directed  upward  and  inward,  and  vibrates  to  produce  the  voice. 
They  are  covered  internally  by  a  very  thin  layer  of  mucous  membrane,  through 
whieli  they  appear  as  white  bands  in  laryngoscopic  examination.  They  are  longer 
in  the  adult  male  than  in  women  and  children. 

The  Rima  Glottidis,  or  chink  of  the  glottis,  is  bounded  in  its  anterior  portion 
on  each  side  by  the  true  vocal  cords,  and  in  its  posterior  portion  on  each  side  by  the 
internal  surfaces  of  the  arj^tenoid  cartilages.  According  to  Krause,  its  length,  in  the 
male,  varies  from  nineteen  to  twenty-five  millimeters,  and  in  the  female,  from  four- 
teen to  seventeen  millimeters.  The  portion  of  the  chink  between  the  true  cords  is 
called  the  glottis  vocalis,  for  it  is  closely  related  to  plionation  ;  the  portion  between 
the  bases  of  the  arytenoid  cartilages  is  called  the  glottis  respiratoria,  because  it  is 
closed  in  j)honation,  and  affords  additional  space  for  passage  of  air  in  respiration. 
In  ordinary  respiration  the  rima  glottidis  is  almost  triangular  in  shape,  but  is 
more  nearh'  of  a  lanceolate  form,  as  there  is  a  slight  angle  at  the  junction  of  the 
tnie  cord  with  the  arytenoid  cartilage.  The  apex  of  the  triangle  or  point  of  the 
lance  is  directed  forward,  and  is  situated  at  the  retiring  angle  of  the  thyroid  car- 
tilage, the  base  lying  between  the  arytenoid  cartilages.  During  phonation  the 
rima  glottidis  is  closed,  and  air  is  forced  through  the  narrow  slit  thus  formed, 
causing  vibration  of  the  thin  free  borders  of  the  true  cords. 

Tile  False  or  Superior  Vocal  Cords  are  not  concerned  in  phonation.  They 
are  two  rounded  folds  of  mucous  membrane  which  cover  two  elastic  bands,  the 
superior  thyro-arytenoid  ligaments.  Below  they  present  a  free,  arched  border, 
which  bounds  the  ventricle  of  the  larynx  above.  They  are  situated  above  the 
true  cords  u])on  each  side  of  the  larynx,  but  as  they  are  more  widely  separated, 
till-  true  eonls  are  seen  between  them  in  a  laryngoscopic  examination.  The  space 
between  tlieni  is  calkMi  the  false  glottis. 

Tlic  Ventricles  or  Sinuses  of  the  Larynx,  one  on  each  side,  are  the  depres- 
sions between  tlie  true  and  false  cords.     They  permit  free  vibration  of  the  true 


PLATE  LXIII. 


Epiglottic 


False  vocal  cord 

Ventficic  of  larynx 

True  vocal  cords — 


Lateral  portion  of  crico-thyroid  membrane 
Central  portion  of  crlco-thyrold  membrane 


Cricoid  cartilage- 


Aryteno-epiglottidean  fold 


Corniculum   laryngis 


Arytenoid  cartilage 
.RIma  glottidis 


Facet  for  inferior  cornu  of  thyroid  cartilage 


LATERAL  VIEW  OF  INTERIOR  OF  LARYNX. 
267 


THE  LARYNX.  269 

cords.  They  partially  uiKlcriuinr  \\\v  i'alsc  eonls,  and  a  probe  or  grooved  director 
passed  into  one  of  them  will  enter  a  divertieuliuu  wliich  passes  beneath  the  ante- 
rior portion  of  the  false  oord,  and  whicii  nsnally  projects  upward  as  high  as  the 
upper  border  of  the  ala  of  tlie  lliymid  cartilage.  This  diverticulum  is  the 
laryngeal  pouch  or  sac.  The  ventricles  of  the  larynx  may  retain  small  foreign 
bodies  which  iiave  entered  the  larynx.  Through  irritation  these  bodies  may  cause 
spasm  of  the  muscles  of  the  larynx  and  asphyxia. 

The  Fossa  Innominata  is  a  depression  situated  behind  the  margin  of  the 
ojiiglottis,  on  the  lateral  wall  of  the  larynx,  and  between  the  aryteno-epiglottidean 
fold  and  the  false  vocal  cord.     It  is  indistinct  except  during  phonation. 

The  Mucous  Membrane  of  the  Larynx  is  thin  and  closely  adherent  over  the 
true  cords,  but  is  thicker,  more  vascular,  and,  excepting  over  the  epiglottis,  loosely 
adherent  elsewhere.  It  is  continuous  above  with  the  mucous  membrane  of  the 
pharvnx,  and  below  with  that  of  the  trachea,  so  that  an  inflammation  of  the 
mucous  membrane  may  spread,  by  continuity,  from  the  pharynx  to  the  larynx 
to  the  trachea.  This  course  is  frequently  observed  in  diphtheria.  Irritation 
of  this  membrane,  as  b}'  a  foreign  body  or  mucus  in  laryngitis,  causes  cough,  or 
spasm  of  the  muscles  of  the  larynx,  as  in  croup  or  laryngismus  stridulus. 

Edema  of  the  mucous  membrane  of  the  larynx  or  edema  of  the  glottis  is 
freciuently  associated  with  severe  attacks  of  acute  laryngitis,  as  after  swallowing 
hot  or  irritating  licjuids  or  the  inhalation  of  irritating  vapors.  Unless  the  submu- 
cous effusion  of  serum  is  allowed  to  escape  by  scarification,  death  may  result  from 
asphyxia.  Intubation  of  the  larynx,  laryngotomy,  or  tracheotomy  may  be 
required  to  prevent  suffocation.  As  the  submucous  tissue  is  more  plentiful  at  the 
superior  aperture  of  the  larynx,  and  especially  upon  the  epiglottis,  the  swelling 
is  most  extensive  in  this  location. 

The  Mucous  Glands  of  the  Larynx  arc  found  in  the  mucous  membrane  of  all 
portions  of  the  larynx  except  over  the  true  cords.  They  are  especially  numerous 
in  the  aryteno-epiglottidean  folds,  in  front  of  the  arytenoid  cartilages,  in  the 
laryngeal  sacs,  an<l  ui)on  the  posterior  surftice  of  the  epiglottis,  in  which  they  are 
lodged  in  pits.  These  glands  keep  the  larynx  moist,  and  tliose  in  the  laryngeal 
sacs  are  especially  active  in  lubricating  the  true  vocal  cords  during  phonation. 
After  long-continued  speaking,  especially  if  in  the  open  air,  these  glands  are 
unable  to  preserve  the  moist  condition  of  the  true  vocal  cords,  and  the  voice 
becomes  husky.  These  same  conditions  are  likely  to  cause  a  determination  of 
blood  to  the  larynx  and  produce  an  acute  lar^mgitis.  When  the  ducts  of  these 
glands  become  occluded,  cystic  tumors  appear  in  the  mucous  membrane  of  the 
larynx. 

Dissection. — Clean  the  cartilages  of  the  larynx,  preserving  the  slender  liga- 


270  SURGICAL  ANATOMY. 

ment  connecting  the  cornicula  larvngis  ■with  the  cricoid  cartilage  {ligamentum 
jugale),  the  superior  thyro-arytenoid  ligaments,  which  are  located  in  the  false  cords, 
the  inferior  thyro-arytenoid  ligaments  or  true  vocal  cords,  and  the  glosso-ej^iglot- 
tidean  and  hyo-epiglottidean  ligaments. 

The  Cartilages  of  the  Larynx  are  nine  in  number — viz.,  the  epiglottis,  thy- 
roid, and  cricoid,  which  are  unpaired,  and  two  arytenoid,  two  cornicula  laryngis, 
and  two  cuneiform  cartilages. 

The  epiglottis  is  composed  of  yellow  elastic  cartilage.  It  is  leaf-like  in  form, 
its  stalk  being  directed  downward  and  attached  to  the  internal  surface  of  the  angle 
of  the  thyroid  cartilage  by  an  elastic  band — the  tliyro-epiglottidean  ligament.  Its 
uppermost  portion  is  free,  and  is  situated  behind  the  lowermost  portion  of  the  base 
of  the  tongue,  the  greater  part  of  which  holds  a  vertical  position  above  it.  Its 
postero-inferior  surface  is  covered  by  mucous  membrane.  It  is  concave  from  side 
to  side,  looks  toward  the  larynx,  and  contains  numerous  pits,  which  are  occupied 
by  mucous  glands.  About  its  center  this  surface  projects  backward  and  forms  a 
low  eminence,  the  cushion  or  tubercle  of  the  epiglottis.  Its  antero-snperior  surface, 
except  in  its  uppermost  portion,  is  not  covered  by  mucous  membrane.  It  is 
convex  from  side  to  side  and  looks  toward  the  thyro-hyoid  membrane,  hyoid  bone, 
and  a  small  portion  of  the  base  of  the  tongue.  This  surface  is  attached  to  the 
thyro-hyoid  membrane  by  intervening  fat  and  loose,  cellular,  elastic  tissue, 
called  the  periglottis.  It  is  attached  to  the  hyoid  bone  by  the  hyo-epiglottidean  liga- 
ment or  hypoglossal  membrane,  which  is  composed  of  elastic  tissue ;  and  to  the 
base  of  the  tongue  by  the  three  glosso-epiglottidean  folds,  which  contain  three  deli- 
cate elastic  glosso-epiglottidean  ligaments.  The  lateral  margins  are  cun-ed  backward  ; 
and  for  nearly  their  whole  extent  are  attached  to  the  aryteno-epiglottidean  folds. 
Into  these  margins  the  aryteno-epiglottidean  and  thyro-epiglottidean  muscles  are 
inserted.     Its  upper  border  is  free  and  curls  forward. 

The  ei)iglottis  is  the  door  which  guards  the  superior  aperture  of  the  larynx. 
It  lies  in  a  vertical  position  during  respiration  and  phonation,  and,  dropping  back- 
ward, closes  the  superior  aperture  of  the  larynx  during  deglutition.  It  is  drawn 
forward  into  the  vertical  position  by  muscles  which  are  attached  to  the  tongue  and 
hyoid  bone — i.  e.,  the  genio-hyo-glossus,  genio-liyoid,  and  mylo-hyoid  muscles. 
The  epiglottis  is  depressed  by  the  aryteno-epiglottideus  and  thyro-epiglottideus 
muscles  ;  they  are  small  and  have  but  slight  power.  Occlusion  of  the  superior 
aperture  of  the  larynx  is  jiroduced  by  elevation  of  that  organ  ;  by  this  means  the 
larjaix  approaches  tlie  base  of  the  tongue,  and  the  epiglottis  is  brought  against  the 
margins  of  the  sujierior  apfrture  of  the  larynx. 

After  the  ejjiglottis  has  been  destroj'ed  by  ulceration,  food  and  liquids  may 
enter  the  larynx  during  deglutition  ;  to  prevent  such  a  disaster  the  patient  should 


PLATE  LXIV. 


pit  for  mucous  gland- 


Superior  cornu  of  thyroid  cartilage 


Mcisura  thyroidece. 


Ala  of  thyroid  cartilage- 


Posterior  border  of  thyroid  cartilage 
Inferior  border  of  thyroid  cartilage 
Inferior  cornu  of  thyroid  cartilage 

Corn.cu.um   laryngis 

Arytenoid  cartilage 


Muscular  process  of  arytenoid  cartilage 


Facet  for  inferior  cornu  of  thyroid  cartilage 


Laryngeal  surface  of  ep'glottis 


Superior  border  of  thyroid  cartilage 


Attachment  of  epiglottis 

Attachment  of  false  vocal  cords 
Attachment  of  true  vocal  coids 

Angle  of  thyroid  cartilage 


Cuneifoim  cartil;:ge 


Cricoid   cartilage 


CARTILAGES  OF  LARYNX, 
271 


THE   LARYXX.  273 

be  fed  tlirougli  a  stoniarli  tulx' ;  nr  \\v  may  successfully  feed  himself  by  leaning  his 
bt^idy  far  furwanl  and  sucking  iiiiuid  food  through  a  tube.  Aftei'  a  time  the  nuis- 
cles  of  tile  larynx  may  act  as  a  sphincter,  thus  preventing  food  from  entering  the 
larynx. 

The  thyroid  cartilage  is  of  the  hyaline  variety,  and  forms  the  greater  piart  of 
the  anterior  and  lateral  walls  of  the  larynx.  It  is  composed  of  two  wings,  or  alte, 
connected  in  the  median  line,  forming  almost  a  right  angle. 

The  alx  are  irregularly  quadrilateral  in  form.  Their  upper  borders,  where 
they  meet  in  the  median  line,  dip  downw^ard,  leaving  a  deep  thyroid  notch  or  in- 
cisura  tlnjroidese.  Behind  they  terminate  in  the  anterior  margins  of  the  superior 
cornua.  Anterior  to  the  superior  cornua  each  ala  presents  a  tubercle,  -which  is 
placed  at  the  upper  end  of  the  oblique  line.  To  the  upper  border  of  the  ake  is 
attached  the  thyrodiyoid  membrane. 

The  lower  border  of  the  cartilage  is  not  so  sinuous  as  the  upper  border  ;  it  ter- 
minates, behind,  in  the  anterior  margins  of  the  inferior  cornua ;  and  presents  a 
tubercle,  which  is  located  at  the  lower  end  of  the  oblique  line.  It  gives  attach- 
ment to  the  central  portion  of  the  crico-thyroid  membrane  and  to  the  crico-thyroid 
muscles. 

The  posterior  border  is  continuous  with  the  posterior  borders  of  the  superior 
and  inferior  cornua.  It  gives  attachment  to  the  stylo-pharyngeus  and  palato- 
pharyngeus  muscles,  and  to  the  pharyngeal  aponeurosis. 

The  external  surface  of  the  ala  presents  an  oblique  line,  which  inclines  down- 
ward and  slightly  forward.  The  oblique  line  gives  attachment  to  the  sterno-tliyroid 
and  thyro-hyoid  muscles.  The  surface  behind  the  obliciue  line  is  covered  by  the 
inferior  constrictor  muscle  of  the  pharynx,  which  arises  just  behind  the  line. 

The  inner  surface  of  the  ala  is  slightly  concave.  It  is  in  relation  with  the 
mucous  membrane  of  the  sinus  pyriformis,  with  the  thyro-hyoid  and  lateral  crico- 
arytenoid muscles,  and  with  the  lateral  portion  of  the  crico-thyroid  membrane. 

The  superior  cornua  are  longer  than  the  inferior,  and  extend  upward,  inward, 
and  backward.  They  are  attached  to  the  greater  cornua  of  the  hyoid  bone  by  the 
thyro-hyoid  ligaments. 

The  inferior  cornua  are  short,  and  directed  downward,  forward,  and  inward. 
On  their  inner  surfaces  they  have  concave  facets  for  articulation  with  the  cricoid 
cartilage.  They  give  attachment  to  the  inferior  constrictor  and  crico-thj'roid 
muscles,  and  to  the  capsular  ligaments  of  the  crico-thyroid  articulations. 

The  anr/le  is  at  the  line  of  junction  of  the  al;e,  is  more  prominent  above, 
where  it  is  called  the  pomum  Adami,  and  lies  beneath  the  inter\'al  between  the 
sternodiyoid  muscles.  Internally  it  gives  attachment,  on  each  side  of  the  median 
line,  to  the  true  and  the  false  vocal  cords.  For  the  purpose  of  making  the  interior 
S—         11—18 


274  SURGICAL  ANATOMY. 

of  the  larynx  accessible,  the  thyroid  cartilage  is  sometimes  split  longitudinally, 
from  the  notch  in  the  upper  border  to  the  lower  border.  In  this  operation  it  is 
important  to  divide  the  cartilage  exactly  in  the  median  line,  so  as  not  to  injure  the 
attachments  of  the  vocal  cords.  When  the  cartilage  has  been  divided,  the  two 
halves  are  turned  aside,  thus  exposing  the  interior  of  the  larynx  and  enabling  the 
operator  to  remove  a  small  tumor  or  foreign  body. 

Fractures  of  the  thyroid  cartilage  are  rare,  but  are  more  common  than  in  the 
other  cartilages  of  the  larynx.  They  are  usually  produced  by  external  direct 
violence,  as  choking  or  throttling,  and  the  line  of  fracture  is  usually  in  the  median 
line,  at  the  angle.  There  are  pain,  swelling,  and  tenderness  in  and  around  the 
larynx,  with  increased  pain  on  swallowing,  coughing,  or  talking.  The  moist 
crepitus  which  can  be  produced  by  forcilily  moving  a  normal  thyroid  cartilage 
laterally  nuist  not  be  mistaken  for  tliat  present  as  a  result  of  fracture. 

Ossification  of  the  thyroid  cartilage  frequently  occurs,  and  may  commence  at 
the  age  of  twenty  years. 

The  cricoid  cartilage  is  the  strongest  of  the  cartilages  of  the  larynx  ;  it  is  a 
tirni  base  which  supports  the  other  portions  of  the  larynx,  and  rests  upon  the 
upper  end  of  the  trachea.  It  is  h3'aline  in  structure,  comjsletely  encircles  the  lower 
portion  of  the  cavity  of  the  larynx,  and,  like  a  signet  ring,  is  broader  behind  than 
in  front. 

Its  external  surface  gives  origin,  in  front,  to  the  crico-thyroid  muscle,  and,  at 
the  side,  to  the  inferior  constrictor  muscle  of  the  pharynx.  Where  its  lateral 
aspect  joins  the  posterior  there  is  a  facet  for  articulation  with  the  inferior  cornu  of 
the  thyroid  cartilage.  The  posterior  poi'tion  of  this  surface  presents  a  median 
ridge,  which  gives  origin  to  the  longitudinal  muscular  fibers  of  the  esophagus, 
and  a  depression  on  each  side  of  the  ridge,  which  gives  origin  to  the  posterior 
crico-arytenoid  muscles. 

The  upper  border  is  horizontal  for  a  sliort  distance,  but  is  soon  directed 
obliquely  downward  and  forward.  Where  the  oblique  portion  begins  there  is  a 
facet  upnn  wliich  the  base  of  the  arytenoid  cartilage  rests.  The  anterior  and  lateral 
portions  of  tlie  upper  border  give  attachment  to  the  crico-thyroid  membrane  and 
tlic  lateral  crico-thyroid  muscle. 

Tlie  inferior  border  is  horizontal.  It  is  attached  to  the  first  ring  of  the  tracliea 
by  fil)rous  inembrane  like  tliat  between  the  tracheal  rings.  The  internal  surface  is 
covered  by  tlie  mucous  membrane  of  the  larynx. 

Ossification  is  not  uncommon  in  the  cricoid  cartilage,  but  in  tlie  smaller 
cartilages  of  tlie  larynx  that  stage  of  development  is  seldom  attained. 

The  cuneiform  cartilages,  or  cartilages  of  Wrisberg,  should  next  be  studied. 
They  are  two  small  conic  ina.sses  of  yellow  elastic  cartilage  situated  in  the  aryteno- 


TlIK    l.Ain'XX.  275 

epiglottidran  folds,  just   antrridi-  to  the  cornicula  larvngis.      Sometimes  the}'  are 
long  and  elub-shaiied  ;  oiH-isioiially  they  are  absent. 

The  cornicula  laryngis,  or  cartilages  of  Santorini,  are  two  ])yraniidal  masses 
of  yellow  elastic  eartila,i;i'  situated  upon  the  summits  of  the  arytenoid  cartilages  in 
the  aryteno-epiglottidean  folds.  Tlay  are  directed  inward.  There  may  be  a  joint 
between  them  and  the  aryttiioid  cartilages,  <n-  they  may  be  directly  continuous  M'itii 
those  cartilages.  Tiieii-  summits  are  attached  to  the  upjier  border  of  IIr-  jioslerior 
portion  of  the  I'ricoid  cartilage  by  the  ligamentum  jugale.  Tlie  ligamentum  jugale 
is  Y-shai>ed,  the  stem  of  the  Y  being  attached  to  the  cricoid  cartilage  and  the  two 
limbs  to  the  summits  of  the  cornicula  laryngis. 

The  cornicula  laryngis  and  tanu'iform  cartilages,  on  larj'ngoscopic  examina- 
tion, appear  as  two  whitish  swellings  in  the  i)Osterior  extremity  of  each  aryteno- 
epiglottidean  fold. 

The  arytenoid  cartilages  are  two  irregularly  pyramidal  bodies,  which  rest 
upon  the  upper  border  of  the  posterior  portion  of  the  cricoid  cartilage.  Their 
greater  portion  is  composed  of  hyaline  cartilage ;  the  remainder,  their  apices, 
being  yellow  elastic  cartilage.  Each  has  an  apex,  a  base,  three  sides,  three  bor- 
ders, ami  three  angles.  The  apex  is  directed  ujiward,  backward,  and  inwai'd,  and 
supports  the  cornieulum  laryngis.  The  base  is  concave,  and  presents  on  its  inner 
side  a  facet  for  articulation  with  the  cricoid  cartilage.  The  three  sides  are  an 
internal,  a  posterior,  and  an  antero-external  or  anterior  surface. 

The  internal  surface  is  directed  toward  the  corresponding  surface  of  the  02)po- 
site  arytenoid  cartilage,  and  is  covered  by  mucous  membrane. 

The  posterior  surface  is  concave,  and  gives  attachment  to  the  arytenoideus 
muscle. 

The  antero-external  or  anterior  surface  is  rough  and  irregular.     It  gives  attach- 
ment to  the  thyro-arytenoideus  muscle  and  tlie  superior  thyro-arytenoid  ligament, 
which  supports  the  mucous  memlirane  of  the  false  vocal  cord. 
The  three  borders  are  the  internal,  external,  and  anterior. 

The  internal  hunJer  is  directed  inward  and  backward ;  the  external  border 
slopes  downward  and  outward  ti.i  the  external  angle;  the  anterior  border  slopes 
downward  and  forward  to  the  anterior  angle.  The  three  angles  are  the  internal, 
external,  and  anterior.  The  internal  angle  is  situated  at  the  postero-internal  angle 
of  the  base.  It  gives  attachment  to  the  transverse  or  crico-arytenoid  ligament. 
The  external  angle  or  muscular  process  is  located  at  the  external  angle  of  tlie  base. 
It  gives  attachment  anteriorly  to  the  lateral  crico-arytenoid  muscle,  and  posteriorly 
to  the  posterior  crico-arytenoid  muscle.  The  anterior  angle  or  vocal  process,  situ- 
ated at  the  anterior  angle  of  the  l)ase.  is  long  and  pointed,  and  gives  attachment  to 
the  true  vocal  cord  or  inferior  thyro-arytenoid  ligament. 


27G  SURGICAL  ANATOMY. 

The  hyaline  cartilages  of  the  larynx — namely,  tlie  thyroid,  cricoid,  aryte- 
noid, and  cartilage  triticea — frequently  undergo  ossification. 

When  any  of  the  cartilages  of  the  larynx  are  fractured,  the  patient  should  be 
placed  on  his  back,  prohibited  from  talking,  and  fed  through  the  rectum  ;  it  may 
be  necessary  to  practise  intubation,  laryngotomy,  or  tracheotomy. 

The  Joints  of  the  Larynx  are  the  crico-thyroid  and  crico-arytenoid. 

The  crico-thyroid  joints  arc  formed  by  the  articulation  of  the  inferior  cornua 
of  the  thyroid  cartilage  with  the  cricoid  cartilage.  They  are  lined  by  synovial 
membrane,  and  have  capsular  ligaments  wliich  are  stronger  posteriorly.  Their 
movements  are  gliding  of  the  cricoid  cartilage  ujiward  and  backward,  and  rotatory 
around  a  transverse  axis. 

The  crico-arytenoid  joints  are  formed  l>y  the  articulation  of  the  cricoid  carti- 
lage with  the  bases  of  the  arytenoid  cartilages.  They  have  a  capsular,  a  posterior 
crico-arytenoid,  and  a  transverse  or  crico-arytenoid  ligament ;  and  each  has  a  syno- 
vial membrane.  The  capsular  ligament  is  loose  and  allows  free  movement.  The 
posterior  crico-arytenoid  ligament  arrests  the  forward  movement  of  the  arytenoid 
cartilage.  The  transverse  or  crico-arytenoid  ligament  connects  the  upper  border 
of  the  cricoid  cartilage  with  the  internal  angles  of  the  arytenoid  cartilages.  The 
crico-arytenoid  joints  permit  of  the  arytenoid  cartilages  gliding  inward  or  outward 
or  rotating  around  a  vertical  axis.  These  movements  permit  the  vocal  processes  to 
rotate  inward  and  the  arytenoid  cartilages  to  be  drawn  together,  closing  the  rima 
glottidis,  as  in  phonation  ;  or  they  allow  the  vocal  processes  to  rotate  outward  and 
the  arytenoid  cartilages  to  be  separated,  thus  opening  the  rima  glottidis  as  in  res- 
piration. 

The  Ligaments  of  the  Larynx  not  associated  with  the  joints  are  the  thyro- 
hyoid and  crico-th3a'oid  membranes ;  the  thyro-hyoid  ligaments,  which  have  been 
described  ;  the  superior  thyro-arytenoid  ligaments,  described  with  the  false  vocal 
cords ;  and  the  inferior  thj^ro-arytenoid  ligaments,  described  as  the  true  vocal 
cords. 

In  Laryngoscopic  Examination  the  patient  should  sit  at  a  higher  level  than 
the  physician  ;  his  tongue  should  be  drawn  foi'ward  so  that  the  base  of  that  organ 
will  not  hang  backward  over  the  epiglottis  and  superior  aperture  of  the  larj'nx  ; 
his  head  should  be  thrown  backward  so  that  the  reflection  of  the  interior  of  the 
larynx,  instead  of  the  image  of  the  base  of  the  tongue,  will  be  seen.  When  the 
mirror  has  been  introduced  into  the  oro-pharynx,  its  handle  must  usually  be 
depressed.  The  epiglottis  will  be  seen  in  its  u])per  ]iart;  the  arytenoid  cartilages, 
cartilages  of  Santorini  and  Wrisberg,  in  its  lower  part ;  the  fiilse  vocal  cords,  ven- 
tricles, and  true  vocal  cords,  on  their  corresponding  sides  ;  and  the  anterior  wall  of 
the  trachea  and,  occasionallv,  its  bifurcation  mav  be  seen.     The  true  vocal   cords 


PLATE  LXV. 


/ 


Prominence  produced  by  sterno 
mastoid  m. 

Common  line  of  incision  for 
laryngotomy,  high  tracheotomy 

and  low  tracheotomy 


Ridge  over  clavicle 

Supraclavicular  fossa 


Segment  of  line  locating 

incision  in  laryngotomy 

Segment  of  line  locating 

incision  in    high  tracheotomy 

_Segment  of  line  locating 
incision  in  low  tracheotomy 


Suprasternal  fossa 
Fossa  supraclavicularis  minor 


SURFACE  MARKS  OF  NECK  AND  LINES  UP  INCISIONS  FOR  LARYNCOTOMY 

278 


^D  TRACHEOTOMY. 


PLATE  LXVI, 


Superficial  layer  of  deep  fascia 

Superficial  f. 

Ski 
Cricoid  cartilage 
Pre'.racheal  fascia 
Sterno-hyoid  m. 


Thyroid  cartilage 

geal  lymphatic  gland 

•thyroid  a. 

co-thyroid  membrane 

ision  into  crico-thyroid  membrane 


Sterno-hyoid  m. 

Pretracheal  fascia 

Incision  into  trachearl 
Isthmus  of  thyroid  body  1 

Cricoid  cartilage  \ 

Two  divisions  of  superficial  layer  of  deep  fascia 


I  fasci 


Supe 


Pretracheal  fascia 
Trachea 
Incision  into  trachea 
Isthmus  of  thyroid  body 
Two-division  of  superficial  l.-^yer  of  deep  fascia 


' 


HIGH  TRACHEOTOMY. 


LARYNGOTOMY. 
279 


LOW  TRAGHEOTOMY, 


THE  LAliyyX.  281 

appear  us  wliitc  hamls  more  nearly  approximated  than  the  false  cords.  In  acute 
laryngitis  tiie  inu-  vixal  conls  are  of  a  pinkish  color,  and  the  remainder  of  the 
larynx  is  rrd  and  swollen.  This  swelling,  or  edema,  of  the  glottis  is  produced  by  a 
serous  inHltratimi  intn  the  suhimicous  areolar  tissue  ;  and  if  present  to  a  marked 
degree,  is  best  treated  by  .scarification  ;  it  may,  however,  necessitate  intubation, 
laryngotomy,  or  tracheotomy. 

The  Hyoid  Bone  is  an  important  adjunct  to  the  larynx.  It  prevents  collapse 
of  the  pharynx  over  the  sujierior  aperture  of  the  larynx,  and  from  it  the  larynx 
is  suspende<l  by  the  thyro-hyoid  memhrane  and  thyro-hyoid  ligaments.  The 
greater  cormia  of  this  bone  are  important  guides.  The  tip  of  the  greater  cornu  is 
oppcsite  the  origin  of  the  lingual  artery,  just  above  the  level  of  that  of  tlie 
superior  thyroid  artery,  and  just  below  the  level  of  the  origin  of  the  facial  artery. 
In  the  operation  for  ligation  of  the  lingual  artery  in  the  lingual  triangle  the 
incision  is  made  just  above  and  parallel  with  the  greater  cornu  of  the  hj'oid  bone. 
This  l)one  is  sometimes  fractured  l)y  external  violence,  as  in  choking  or  throttling, 
and  has  been  l)r(>ken  Ijy  muscular  action.  The  Ijod}'  of  the  bone  is  rarely  frac- 
tured, one  of  the  greater  cornua  usually  being  fractured. 

The  Movements  of  the  Larynx  oi  masse  are  in  but  two  direction.? — upward 
and  downward.  The  most  marked  movements  are  performed  during  deglutition, 
prior  to  which  the  larynx,  as  well  as  the  pharynx,  is  drawn  upward.  By  this 
means  closure  of  the  superior  aperture  of  the  larynx  is  facilitated,  and  elevation  of 
the  pharynx  aids  the  constrictor  muscles  of  the  pharynx  to  grasp  the  morsel  of 
food.  The  larynx  is  elevated  by  the  following  muscles :  The  digastric,  the  stylo- 
hyoid, the  mylo-hyoid,  the  genio-hj'oid,  the  lower  portion  of  the  geniodiyo-glossus, 
the  stylo-pharyngeus,  and  the  palato-pharyngeus.  It  is  depressed  by  the  sterno- 
hyoid, the  sterno-thyroid,  and  the  omo-hyoid  muscles. 

Laryngotomy  is  performed  through  the  crico-th3'roid  membrane.  The 
shoulders  are  elevated  by  a  jjillow,  the  head  and  neck  are  extended,  a  firm  support 
is  placed  under  the  neck,  and  the  face  is  made  to  look  directly  forward  so  that 
the  relations  of  the  structures  in  the  median  line  of  the  neck  may  not  be  distorted. 
The  thyroid  and  cricoid  cartilages  and  the  crico-thyroid  space  are  outlined,  the 
larynx  is  gently  steadied  with  the  thumb  and  fingers  of  one  hand,  and  an  inci- 
sion one  and  one-half  inches  long  is  made  in  the  median  line  over  the  lower  jiart 
of  the  thyroid  cartilage,  the  crico-thyroid  membrane,  and  the  cricoid  cartilage.  The 
skin,  the  superficial  fascia,  and  the  superficial  layer  of  the  deep  fascia  are  divided ; 
the  sterno-hyoid  and  sterno-thyroid  muscles  are  separated  from  the  corresponding 
muscles  of  the  opposite  side  ;  the  pretracheal  fascia  is  divided  ;  and  the  central  jwr- 
tion  of  the  crico-thyroid  membrane  is  divided  transverselj'  along  the  upper  border 
of  the  cricoid   cartilage.      By  dividing  the  lowest  portion  of  the  membrane  the 


282  SURGICAL   AS  ATOMY. 

crico-thj'roid  arteries  and  the  true  vocal  cords  are  avoided,  and  if  the  knife  is 
directed  downward  and  backward,  the  vocal  cords  are  in  less  danger. 

Excision  of  the  Larynx  is  sometimes  performed  for  removal  of  malignant 
disease  of  tliat  organ  ;  but  tlie  results  of  the  operation  are  so  discouraging  that  a 
palliative  tracheotomy  is  usually  preferred. 

The  Trachea  is  directly  continuous  with  the  lower  jiortion  of  the  larynx,  so 
that  the  larynx  appears  to  be  the  upper  extremity  of  the  trachea  modified  for  the 
performance  of  certain  special  functions.  The  trachea  varies  between  four  and 
one-half  and  five  inclies  in  length  and  three-fourths  of  an  inch  and  one  inch  in 
width.  On  transverse  section  it  is  shaped  like  a  l)ar  horseshoe,  the  indentation 
being  posteriorly  for  tlie  acconnnodation  of  the  esophagus.  The  trachea  is  com- 
posed of  cartilaginous  rings,  which  are  connected  by  fibrous  membrane.  The 
rings  are  horseshoe-shaped,  with  the  open  end  posteriorly  ;  this  interval  is  filled  by 
the  fibro-elastic  membrane,  which  yields  to  pressure  of  bodies  passing  through  the 
esophagus,  thus  providing  additional  space  during  deglutition.  The  trachea  con- 
tains from  sixteen  to  twenty  of  these  rings,  seven  or  eight  of  which  are  above  the 
upper  margin  of  the  sternum.  Wlien  tlie  head  and  neck  are  in  the  long  axis  of 
the  body,  about  two  inches  of  tlie  trachea  are  above  the  sternum,  and  by  full 
extension  of  the  head  and  neck  this  distance  may  be  increased  to  three  inches. 
The  trachea  is  cjuite  superficial  at  its  upper  exti'emity,  but  rapidh'  becomes  deeply 
situated  as  it  descends  ;  this  is  one  of  the  reasons  for  preferring  high  tracheotomy. 

Relations  of  the  Cervical  Portion  of  the  Trachea. — In  front  are  the 
skin  ;  the  superficial  fascia;  the  superficial  layer  of  tlie  deep  fascia,  which  is  here 
composed  of  two  layers ;  a  communicating  branch  between  the  anterior  jugular 
veins,  situated  just  above  the  sternum  ;  the  sterno-hyoid  and  sterno-thyroid  mus- 
cles ;  the  isthmus  of  the  thyroid  bodj' ;  the  inferior  thyroid  veins  or  thyroid  plexus 
of  veins ;  occasionally,  the  thymus  gland  or  the  remains  of  that  gland  ;  the  pre- 
tracheal fascia,  and  the  thyroidea  ima  artery  when  present.  Occasionally,  a  high 
innominate  artery  or  left  innominate  vein  may  l)e  in  front  of  the  trachea  at  the 
root  of  the  neck.  Behind  the  cervical  portion  of  the  trachea  is  the  esophagus. 
On  each  side  of  it  are  the  lateral  lobes  of  the  th3'roid  bod}',  the  recurrent  larjm- 
geal  nerves,  the  terminal  portions  of  tlie  inferior  thyroid  arteries,  and  the  carotid 
sheaths  inclosing  the  CDiiiiiioii  carotid  arteries,  interiuil  jugular  veins,  and  pneumo- 
gastric  nerves.  The  trachea  will  be  more  completely  described  under  the  section 
on  the  Chest. 

Tracheotomy. — The  windpipe  may  be  opened  either  aboA'e  or  below  the 
isthmus  of  the  thyroid  gland  ;  the  former  procedure  being  known  as  high,  the 
latter  as  low,  tracheotomy.  High  tracheotomy  is  the  easier  of  the  two  operations, 
because  the  first  part  of  the  trachea  is  less  deeply  jilaced  and   is  somewhat  larger 


THE   LARYXX.  283 

ami  less  mobilo,  boinji,  thcrcfoix',  more  accesssible  than  the  part  just  abovt-  the 
stiTiiuiii.  Furthermore,  the  inferior  thyroid  veins,  lying  upon  the  trachea  below 
the  isthnuis,  the  oeeasional  presence  of"  a  thyroidea  inia  artery,  and  in  infants  the 
upper  part  of  the  thynnis  gland,  add  to  the  ditticulties  of  the  low  operation.  It  is 
also  to  be  remembered  thai  the  iiniDmiuate  artery  or  the  left  iumiminate  vein  may 
cross  the  trachea  hiyher  than  usual  and  might  he  eiicuuiitercd  in  the  low  opera- 
tion. 

For  the  performance  of  the  operation  the  head  is  well  extended  and  so  held 
by  an  assistant  that  the  median  line  of  the  face  will  be  in  line  with  the  median 
line  of  the  neck.  A  firm  cjdindric  cushion  or  a  large  bottle  is  so  placed  under 
the  back  of  the  neck  as  to  render  its  anterior  region  prominent.  Tlic  parts  are 
steadied  with  the  lingers  and  thuml)  of  one  hand.  The  various  landmarks,  such 
as  the  pomum  Adami  and  the  cricoid  cartilage,  are  recognized  by  palpation.  The 
incision  extends  from  about  the  lower  border  of  the  thyroid  cartilage  downward 
for  two  and  a  half  inches  in  the  median  line.  It  is  made  from  below  upward,  and 
divides  skin  and  superficial  fascia.  The  anterior  jugular  veins,  which  lie  alongside 
of  the  median  line,  may  now  appear,  and  should  be  avoided  by  cutting  between 
them  and  drawing  them  aside.  The  two  layers  of  the  superficial  layer  of  the  deep 
cervical  fascia  are  then  divided  either  upon  a  director  or  with  the  free  hand.  The 
interval  between  the  flat  pretracheal  muscles  is  recognized,  and  the  wound  deep- 
ened by  "  blunt  dissection  "  ;  the  director  or  the  handle  of  the  knife  being  used 
to  slit  down  the  soft  parts  in  the  median  line  until  the  pretracheal  f;iscia  is  reached. 
The  pretracheal  fascia  is  incised  and  the  tracheal  rings  ai'e  fully  exposed,  the 
director  or  handle  of  the  knee  being  again  used  in  order  to  avoid  hemorrhage. 
The  isthmus  of  the  thyroid  gland  is  depressed,  if  need  be,  to  gain  additional  space. 

Hemorrhage  having  been  checked  and  the  tracheal  rings  fully  exposed, 
the  trachea  is  held  steady  with  a  tenaculum  and  a  sharp  narrow-bladed 
knife,  with  its  cutting  edge  directed  upward,  is  thrust  into  the  windpipe  and  two 
or  three  rings  divided  from  below  upwanl.  The  edges  of  the  tracheal  wound  are 
tlu^n  held  apart  with  a  dilator,  hooks,  or  a  loop  of  silk  jiassed  through  each 
side.  False  membrane,  if  present,  is  withdraAvn,  and  the  tracheal  tube  is 
inserted. 

xVfter  opening  the  windpipe  it  will  usually  l_)e  noticed  that  respiration  is  much 
slower,  owing  to  the  fiict  that  plenty  of  air  is  admitted  ;  whereas  prior  to  the 
operation  the  breathing  was  Imrried,  on  account  of  the  obstruction. 

It  is  important  during  the  operation  that  the  trachea  be  kept  exactlj-  in  the 
median  line,  otherwise  it  may  be  opened  on  one  side,  or,  from  being  careles.sly 
drawn  to  one  side  by  the  assistant,  it  may  be  missed  altogether,  and  the  operator, 
as  has  occurred,  may  expose  the  vertebral  column  before  the  error  is  recognized. 


284  SURGICAL  ANATOMY. 

It  is  also  essential  to  thoroughly  expose  the  rings  of  the  trachea  by  clearing  away 
the  pretracheal  fascia ;  such  exposure  prevents  the  mistake  of  introducing  the 
tracheal  tube  under  that  fascia,  instead  of  into  the  windjjipe,  thereby  increasing 
the  respiratory  difficult}'. 

In  children  the  cricoid  cartilage  is  sometimes  divided  in  addition  to  the 
tracheal  rings,  thus  converting  the  operation  into  a  larj^ngo-tracheotomy. 

In  the  low  operation  the  same  general  rules  are  observed  as  in  the  high 
operation ;  the  incision  extends  from  the  top  of  the  sternum  to  the  cricoid  carti- 
lage. After  division  of  the  skin  and  fascia^  the  wound  is  deepened  by  blunt 
dissection,  for  there  is  here,  of  course,  more  danger  of  hemorrhage  than  in 
the  previously  described  operation.  The  inferior  thyroid  veins,  or  thyroid  plexus 
of  veins,  which  lie  upon  the  j^i'etracheal  fascia,  should  be  displaced,  and  the 
trachea  thoroughly  exposed,  the  forefinger  being  passed  into  the  wound  from 
time  to  time  as  the  wound  is  deepened,  in  order  to  ascertain  the  relations  of 
the  tissues,  recognize  abnormal  vessels,  and  feel  the  tracheal  rings. 


THE  NOSE. 

The  Nose  is  the  uppermost  portion  of  the  respiratory  tract.  It  contains  the 
special  organs  of  the  sense  of  smell,  and  removes  particles  of  dust  from  and  warms 
and  moistens  the  inhaled  air ;  therefore,  M^hen  the  nasal  passages  are  occluded, 
disease  of  the  lower  i^ortion  of  the  respiratory  tract  is  more  likely  to  occur.  It 
may  be  divided  into  the  nose  proper  and  the  nasal  cavities  or  fossae. 

The  Nose  proper  resembles  a  jiyramid  with  three  sides,  the  i^osterior  of 
which  is  wanting  and  directed  toward  the  nasal  cavities.  The  two  lateral  surfaces 
are  triangular,  covered  by  skin,  and  form  a  part  of  the  face.  The  apex  of  the 
pyramid — the  root  of  the  nose — joins  the  forehead.  Below  its  root  it  broadens  into 
the  bridge  or  dorsum  of  tlie  nose.  Sinking  of  the  bridge  of  the  nose  occurs  in 
children  who  are  affected  by  congenital  syphilis,  and  who  suffer  from  syphilitic 
coryza  or  "  snuffles."  The  severe  nasal  catarrh  modifies  the  nutrition  of  the 
surrounding  structures,  and  causes  imperfect  development  of  the  adjacent  bones. 
The  two  lateral  borders  of  the  nose  are  coiitinuons  with  the  face.  The  anterior 
border  is  free,  and  terminates  below  in  the  lobule  or  tip  of  the  nose.  The  lateral 
surfaces,  below,  slope  outward  into  the  alse  or  wings  of  the  nose,  which  form 
the  lower  borders  of  those  surfaces. 

The  base  of  the  nose  presents  two  apertures,  the  anterior  nares,  or  nostrils, 
which  are  separated  by  a  median  pillar  or  columna.       The  anterior   nares  are 


THE  NOSE.  285 

guarded  internally  by  short  stiff  hairs,  or  vihrissa?,  which  sift  small  bodies  out  of 
the  inhaled  air.  The  anterior  naros  open  into  the  vestibule  of  the  nose,  which  is 
the  portion  of  the  nasal  cavities  within  the  cartilaginous  portion  of  the  nose 
proper.  As  the  base  of  the  nose  is  in  a  slightly  lower  plane  than  the  floor  of  the 
nasal  fosste,  the  base  of  the  nose  should  be  elevated  with  the  speculum  in  making 
an  examination  of  the  nasal  cavities. 

The  walls  uf  the  nose  proper  ai-e  formed  above  by  the  nasal  bones,  the  nasal 
spine  of  the  frontal  bone,  and  the  nasal  processes  of  the  superior  maxillary  bones ; 
and,  below,  by  the  lateral  cartilages  of  the  nose. 

The  skin  is  loosely  adherent  to  the  upper  part  of  the  nose,  but  is  closely 
attached  over  the  alae  and  lobule.  It  contains  sebaceous  glands,  which  are  espe- 
cially numerous  at  the  lower  part  of  the  nose.  Therefore,  acne  and  comedones  are 
common  in  this  location.  Acne,  or  pimples,  and  other  inflammatory  affections 
upon  the  alas  and  lobule  of  the  nose  are  painful  on  account  of  the  density  of  the 
tissues,  which  prevents  swelling  and  causes  increased  pressure  on  the  nerves.  The 
skin  of  the  nose  is  also  commonly  affected  by  acne  rosacea  and  lupus,  especially 
lupus  erythematosus,  which  develops  upon  the  nose,  ears,  and  face  more  frecjuently 
than  on  other  portions  of  the  body.  Rodent  ulcer,  another  affection  which  has  a 
predilection  for  the  nose,  frequently  commences  in  the  crease  between  the  cheek 
and  the  ala  of  the  nose.     This  is  a  not  uncommon  site  for  epitJielioma. 

Blood  Supply. — The  nose  proper  is  supplied  by  the  nasal,  angular,  infra- 
orbital, lateral  nasal,  and  superior  coronary  arteries.  The  numerous  and  freely 
anastomosing  vessels  of  the  exterior  of  the  nose  communicate  M'itli  those  in  the 
mucous  membrane  ;  hence  it  happens  that  in  many  cases  of  inflammatory  disease 
of  the  nasal  mucosa  there  is  congestion  of  the  cutaneous  vessels. 

On  account  of  its  free  blood  supply,  the  skin  of  the  nose  offers  a  good  field 
for  plastic  operations.  Restoration  of  the  nose  by  a  plastic  operation  is  known 
as  rhinoplasty.  The  flap  may  be  derived  from  the  forehead,  as  in  the  Indian 
method,  or  from  the  inside  of  the  arm,  as  in  the  Tagliacotian  method.  The  flaps 
may  also  be  taken  from  the  cheeks,  or  the  flaps  from  the  cheeks  may  be  placed 
with  their  cutaneous  surface  inward  and  covered  with  a  flap  from  the  forehead. 
In  the  nose,  as  in  the  scalp,  the  free  blood  supply  prevents  sloughing  of  portions 
of  the  organ  almost  cut  away  and  then  reposited,  and  small  scars  are  formed 
in  the  repair  of  wounds. 

Nerve  Supply. — The  nose  proper  is  supplied  by  the  nasal,  infra-trochlear, 
and  infra-orbital  nerves.  The  muscles  of  tlie  nose  proper,  which  have  been 
considered  with  the  description  of  the  face,  are  supplied  by  the  facial  nerve. 

The  veins  of  the  nose  proper  empty  into  the  ophthalmic  and  facial  veins. 
There  is  a  network  of  rather  large  anastomosing  veins  in  the  tip  of  the  nose. 


286  SURGICAL  AXATOAIV. 

The  lymphatics  of  the  nose  i)roiier  pass  to  the  submaxillary  lymphatic  glands. 

Because  of  their  exposed  position  and  the  absence  of  subcutaneous  fat  whicli 
protects  underlying  vessels,  the  lobule  and  alse  of  the  nose,  like  the  pinna  of  the 
ear,  are  frequently  fi'ozen  and  may  be  the  site  of  gangrene  resulting  therefrom. 

Dissection. — Remove  the  tissues  covering  the  nasal  bones  and  lateral  car- 
tilages of  the  nose. 

The  nasal  bones  are  tliick  and  narrow  at  their  upper  extremities,  and  tliin, 
broad,  and  much  exposed  to  injury  at  their  lower  portion  ;  consequently  these 
bones  are  more  frequently  fractured  near  their  lower  margins.  A  blow  at  the  root 
of  the  nose  is  far  more  likely  to  break  the  cribriform  plate  of  the  ethmoid  bone 
and  the  anterior  walls  of  the  frontal  sinuses  tlian  the  nasal  bones.  Fractures  of 
the  nasal  bones  may  be  reduced  by  manijmlation  of  the  fragments  between  the 
fingers  externally  and  a  grooved  director  introduced  into  the  nasal  fossse.  Owing 
to  their  vascularitj^,  the  nasal  bones  unite  quickly.  In  congenital  syphilis  destruc- 
tion of  the  bones,  especially  of  those  of  the  septum,  causes  the  bridge  of  the  nose 
to  sink.  Congenital  protrusions  of  the  membranes  of  the  brain  or  the  brain 
itself  may  occur  at  the  root  of  the  nose.  They  are  known  as  sincijiital  meningo- 
celes and  encephaloceles,  ami  appear  because  of  incomplete  union  of  tlie  frontal 
bone  with  the  cribriform  plate  of  the  ethmoid  bone  and  with  the  nasal  bones. 
The  skin  over  these  tumors  may  bo  highly  vascular  and  present  some  resemblance 
to  that  over  a  nevus. 

The  cartilages  in  the  framework  of  the  nose  consist  of  a  superior  and  an 
inferior  lateral  cartilage  and  sesamoid  cartilages  on  each  side,  and  the  cartilage  of 
the  septum. 

The  superior  lateral  cartilages  are  triangular.  Their  anterior  margins  are 
partly  continuous  with  the  anterior  border  of  the  cartilage  of  the  septum,  to  which 
they  are  closely  applied.  Their  posterior  margins  are  closelj^  united  to  the  superior 
maxilla)  and  the  lower  border  of  the  nasal  bones.  Their  inferior  borders  are 
attached  to  the  inferior  lateral  cartilages.  Their  outer  surfaces  ai'e  covered  by  tlie 
skin  and  the  nmscular  and  iil irons  tissue  of  the  nose;  and  their  inner  surfaces  by 
the  nasal  mucous  membrane.  When  the  superior  lateral  cartilage  is  detached 
iVdiii  tlio  nasal  bone  liy  traumatism,  considerable  pain  in  the  no.se  is  produced 
by  injury  of  the  nasal  nerve,  which  emerges  between  this  cartilage  and  the  nasal 
bone. 

The  i)ifcrior  hitcral  rarfilnr/i's  are  sharply  bent  around  in  front  of  tlie  anterior 
nares,  so  that  tluy  are  composed  of  an  inner  and  an  outer  portion.  The  inner 
portion  lies  in  contact  with  the  corresponding  portion  of  the  opposite  inferior 
lateral  cartilage  on  the  inner  side  of  tiie  anterior  naris,  forming  part  of  the  col- 
umna.     The  outer  jiortiun  is  oval  and  curves  backward  in  the  ala  of  the  nose.     It 


PLATE  LXVII 


V'  \ 


Superior  lateral  cartilage 
Accessory  quadrate  cartilages 

Cartilage  of  nasal  septum 


.    1 


^ 


Nasal  bone 


*T^„ 


Inferior  lateral  cartilage 


J 


Sesamoid  cartilages 


Fibrous  tissue  of  ala  of  nose 


LATERAL  CARTILAGES  OF  NOSE. 
287 


11—19 


PLATE  LXVIII 


Cartilage  of  septum  of  nose 


Inferior  lateral  cartilage 


Anterior  nans 


if\      Fibrous  tissue  of  ala  of  nose 


Anterior  nasal  spine 

uf  superior  nnaxilla 


CARTILAGES  AT  BASE  OF  NOSE. 
290 


PLATE  LXIX, 


Vertical  plate  of  ethmoid 


Sphenoid  sinus 


Septal  cartilage 
Inferior  lateral  cartilage  of  nose 


Vomer 
Groove  for  naso-palatine  n. 


NASAL  SEPTUM. 
291 


THE  NOSE.  293 

is  attached  to  the  superior  hitenxl  cartilage  and  the  superior  maxilla  by  dense 
tibrous  tissue,  in  which  the  sesamoid  cartilages  are  found.  The  margin  of  the 
alae  of  the  nose  is  not  formed  by  the  inferior  lateral  cartilage,  but  by  the  dense 
fibrous  tissue  which  forms  the  framework  of  the  nose  projier  where  the  bones 
and  cartilages  are  absent. 

The  sesamoid  or  accessory  cartilages  are  usually  four  in  number  in  each  lateral 
■wall  of  the  nose  proper.  Two  of  these  cartilages  are  situated  in  the  fibrous  tissue 
which  connects  the  inferior  lateral  cartilage  with  the  nasal  process  of  the  superior 
maxilla.  Just  above  these  are  the  other  two,  which  are  called  the  accessory  quadrate 
cartilages.  Additional  sesamoid  cartilages  may  be  found  in  the  fibrous  tissue 
which  completes  the  framework  of  the  nose  proper,  but  the  four  previously 
mentioned  are  the  only  constant  sesamoid  cartilages. 

The  septal  cartilage  is  placed  in  the  antero-inferior  portion  of  the  septum,  fill- 
ing the  angular  interval  between  the  vertical  plate  of  the  ethmoid  bone  and  the 
vomer.  It  is  quadrilateral  in  form.  Its  posterior  superior  border  is  in  contact 
with  the  vertical  plate  of  the  ethmoid  bone,  which  is  sometimes  grooved  to 
receive  it.  Its  posterior  inferior  border  joins  the  anterior  nasal  spine  of  the 
superior  maxilla,  and  the  vomer,  which  may  be  grooved  for  its  reception.  The 
upper  portion  of  its  anterior  superior  border  is  attached  to  the  crest  on  the 
under  surface  of  the  junction  of  the  nasal  bones,  and  below  the  nasal  bones  the 
sides  of  this  border  are  continuous  with  the  superior  lateral  cartilages ;  it  termi- 
nates just  above  the  tip  of  the  nose  between  the  inner  plates  of  the  two  inferior 
lateral  cartilages.  The  anterior  inferior  border  is  short,  and  extends  backward  and 
downward,  above  the  columna,  to  the  anterior  nasal  spine,  which  it  embraces. 

The  cartilages  and  other  soft  tissues  of  the  cartilaginous  portion  of  the  nose 
may  be  destroyed  by  lupus  vulgaris,  the  bones  not  being  involved.  The  nose  maj'' 
be  repaired  by  one  of  the  methods  of  jtlastic  operation  (rhinoplasty)  previously 
mentioned. 

Dilating  specula  introduced  into  the  anterior  nares  should  not  be  inserted 
beyond  the  cartilaginous  portion  of  the  nose,  on  account  of  the  pain  produced  by 
pressure  upon  resisting  bony  structures. 

Dissection. — Hold  the  anterior  segment  of  the  skull  so  that  the  light  enters 
the  nasal  cavities  through  the  anterior  nares,  or  pass  a  probe  or  a  grooved  director 
into  the  nasal  cavities  to  determine  to  which  side  the  nasal  septum  is  deflected. 
Then  cut  through  the  tissues  of  the  upper  lip  and  through  the  lateral  cartilages, 
close  to  that  side  of  the  septum  which  does  not  bulge,  ^^lth  the  hard  palate  facing 
upward  saw  through  the  skull,  close  to  the  flat  or  concave  side  of  the  septum.  The 
superior  turbinated  bone  on  one  side  may  be  broken,  in  which  case  it  may  be 
studied  on  the  other  side  after  removing  the  septum. 


294  SURGICAL   ANATOMY. 

Tlie  Nasal  Cavities,  or  Fossae,  two  in  number,  are  located  between  the  base 
of  the  skull  and  the  hard  palate.  They  are  -wide  below-  and  become  quite  narrow 
above,  where  the  middle  and  sui^erior  turbinated  bones  lie  near  the  septum,  and  at 
times  in  contact  with  it.  The  vertical  diameter  of  each  nasal  fossa  is  greater 
than  the  transverse  diameter;  and,  therefore,  forceps  inserted  into  the  fossae  should 
be  opened  vertically.  The  nasal  cavities  open  upon  tiie  face  by  means  of  the 
vestibule  and  anterior  nares,  and  into  the  naso-pharynx  by  means  of  the  posterior 
nares.     They  are  separated  by  the  nasal  sei)tum. 

The  nasal  septum  is  formed  l)y  the  crest  at  the  junction  of  the  nasal  bones, 
the  nasal  spine  of  the  frontal  bone,  the  vertical  plate  of  the  etlimoid  Ijone,  the 
cartilage  of  the  septum,  the  vomer,  the  crest  of  the  sphenoid  bone,  and  by  the 
crest  situated  at  the  line  of  junction  of  the  two  palatal  processes  of  the  two  superior 
maxillse  and  of  the  two  horizontal  plates  of  the  palate  bones.  In  children  up 
to  the  seventh  year  and  in  primitive  races  the  septum  is  straight  in  eighty  per 
cent,  of  cases ;  but  in  the  adult  in  seventy-six  per  cent,  of  persons  it  is  deflected 
to  one  side,  and  more  frequently  to  the  left.  This  deflection  should  not  be  mis- 
taken for  a  bony  growth  of  the  septum. 

The  frequency  of  deviation  of  the  nasal  septum  is  supposed  to  be  due  to 
the  practice  of  alw^ays  blowing  the  nose  with  the  same  hand.  This  condition,  by 
obstructing  one  nasal  fossa,  retards  breathing  and  impairs  the  resonance  of  the 
voice,  which  should  be  perfect  in  those  who  sing. 

Perforation  of  the  nasal  septum  may  occur  in  persons  exposed  to  the  vapor 
of  chromic  acid  in  the  manufacture  of  potassium  l)ichromate,  in  syphilitic  indi- 
viduals, and  in  scrofulous  persons,  or  may  be  a  congenital  condition. 

■  The  roof  of  the  nasal  cavities  is  formed  Ijy  the  nasal  bones,  nasal  spine  of  the 
frontal  bone,  cribriform  plate  of  the  ethmoid  bone,  sj^henoid  turbinated  bones, 
body  of  the  sphenoid  Ijone,  alaj  of  the  vomer,  and  sphenoid  processes  of  the 
palate  bones.  Tlie  middle  portion  of  the  roof,  formed  by  the  cribriform  plate 
of  the  etlnnoid  Ijone,  is  horizontal,  its  anterior  portion  slopes  downward  and 
forward,  and  its  posterior  portion  downward  and  backward.  A  meningocele 
projecting  through  the  roof  of  the  nasal  fossa  into  the  nasal  cavity  has  been 
mistaken  for  a  polypus  and  removed,  with  a  fatal  result.  In  fracture  of  this 
]iortion  of  the  base  of  tlie  skull  blood  or  cerebro-spinal  fluid  may  escape  through 
the  nose. 

The  middle  portion  of  the  roof  of  the  nose  is  so  thin  tliat  it  may  easily  be 
punctured  and  the  cranial  cavity  entered  by  slender  instruments  or  foreign  bodies 
introduced  in  the  nose,  either  intentionally  or  accidentally. 

Tlie  floor  of  the  nose  is  wider  tlian  the  ro5f,  being  slightly  more  or  less  than 
one-half  of  an  inch  wide.     It  is   lornuHl   liy  the  ]ialatal  processes  of  the  superior 


PLATE  LXX. 


Superior  meatus 


Superior  turbinal 
Middle  turbinal 


Inferior  turbinal 
Inferior  meatus 


Vestibule 

Tongue 

Posterior  pillar  of  fauces 

Genio-hyo  glossus  nn 


Genio  hyoid  m 

Hyoid  bone 

Mylo-hyoid  m(cut  edge) 

Thyro-hyoid  membrane  (cut 
edge) 

Ventricle  of  larynx 
Thyroid  cartilage  (cut) 


Diaphragma  sellae 
Cavum  sellae 

Spenoidal  cell 


Middle  meatus 


i 


Naso-pharynx 
Orifice  of  Eustachian  tube 

hlard  palate 
Soft  palate 

Uvula 

Anterior  pillar  of  fauces 

Tonsil  in  recess  of  fauces 
Oro-pharynx 

Epiglottis  (cut  edge) 
Aryteno-epiglottidean  fold 


Laryngo-pharynx 
uprarimal  portion  of  larynx 
False  vocal  cord 
True  vocal  cord 
nfrarimal  portion  of  larynx 

Cricoid  cartilage  (cut) 


Ring  of  trachea 


MEATUSES  OF  NOSE  AND  TURBINATED  BONES-LATERAL  VIEW. 

2m 


PLATE  LXXI, 


Frontal  sinus 

Straw  in  infund'-bulum    ' 

Orifices  of  anterior  ethmoidal  cells 
Bulla  ethmoidalis 

Drifices  of  posterior  ethmoidal  cells  in   superior  meatus 
Superior  turbinal  (cut) 

Straw  in  orifice  of  sphenoidal  cell 
Sphenoidal  cell 

Diaphragma  sellae 
ae 


Middl. 


achian  tube 


Hiatus  semilunaris 


Middle  turbinal  (cut) 
Straw  in  orifice  of  Antrum  of  Highmore 
Additional  orifice  of  Antrum  of  Highmore 
Straw  In  nasal  duct 


ORIFICES  OF  ACCESSORY  AIR-CHAMBERS  OF  NOSE. 
298 


"'^SE.  209 

maxill;i>  ami  the  liorizontal  plates  of  u.,  >(•  bones.     It  is  somewhat  concave 

from  side  to  side,  and  slojies  slightly  dowinvani  and  hackward. 

The  outer  wall  of  the  nasal  fossa  is  formed  hy  the  nasal  iirocess  and  internal 
surfai'c  of  the  snperior  niaxilhi.  the  inferior  turhinalcd  hone,  tin;  latM'vnial  hone, 
the  lateral  mass  of  the  ethmoid  inuie,  the  vertical  platt'  of  the  |i;ilate  hone,  and  the 
internal  pterygoid  plate  of  the  sphenoid  bone.  The  outer  wall  is  made  irregular 
by  projection  of  the  sujierior,  middle,  and  inferior  turl)inatcd  bones  into  the  nasal 
cavity. 

The  superior  turbinated  bone  is  situated  on  the  upjier  part  of  the  outer  wall 
in  the  posterior  one-third  of  the  cavity,  its  anterior  and  highest  portion  l.ieing  about 
opposite  the  tendo  oculi.  The  middle  turbinated  bone  extends  along  the  posterior 
two-thirds  and  the  inferior  turbinated  bone  along  nearly  the  whole  length  of  the 
outer  wall  of  the  nasal  fossa.  The  recesses  beneath  the  turbinated  bones  are  called 
meatuses.  Of  these  there  are  three — viz.,  tlie  superior,  middle,  and  inferior 
meatuses,  each  situated  beneath  the  corresponding  turbinated  ))one.  The  superior 
meatus  is  closed  in  front  and  ojiens  downward  and  backward.  It  contains  the 
oritices  of  the  sphenoid  cells  or  sinuses  and  of  the  posterior  ethmoid  cells. 
The  orifice  of  the  sphenoid  cells  is  really  in  the  roof  of  the  nasal  fossa  at  the 
level  of  the  superior  turbinated  bone,  and  when  that  bone  is  divided  into  two 
plates,  the  orifice  is  oppo.site  the  space  between  them,  known  as  the  fourth  meatus 
or  spheno-ethmoid  recess  of  Meyer.  The  middle  meatus  is  open  in  front, 
behind,  and  below.  In  front  it  opens  into  a  broad  portion  of  the  nasal  cavity, 
called  the  afriinn  of  the  middle  meatus.  The  atrium  opens  widely  anteriorly  into 
the  vestibule,  allowing  most  of  the  inhaled  air  to  jiass  through  the  middle  meatus. 
On  the  lateral  or  external  wall  of  the  middle  meatus  is  a  groove  known  as 
the  hiatus  semilunaris,  which  begins  at  the  lower  extremity  of  the  infundibulum 
and  curves  from  above  backward  and  downwai'd.  The  orifices  leading  to  the 
antrum  of  Highmore  and  to  the  anterior  ethmoid  air  cells  are  in  this  groove. 
Till'  bulla  ethmoidalis  is  the  rounded  upper  boundary  of  the  hiatus  semilu- 
naris. The  orifice  rif  the  antrum  of  Highmore  is  about  an  incli  above  the  floor  of 
the  nose.  The  inferior  meatus  opens  chiefly  downward  and  backward,  so  that 
more  exhaled  than  inhaled  air  passes  through  it.  It  presents  the  inferior  orifice  of 
the  lacrymo-nasal  (nasal  or  lacrymal)  duct,  which  carries  the  tears  from  the 
lacrymal  sac  to  the  nose.  The  opening  of  the  nasal  duct  is  at  the  under  surface  of 
the  attached  margin  of  the  inferior  turbinated  bone,  about  an  incli  behind  the  ante- 
rior hares,  and  three-fourths  of  an  inch  above  the  floor  of  the  no.?e.  Instruments 
to  be  introduced  into  the  inferior  meatus  must  be  directed  toward  the  floor  of  the 
nose,  or  the  anterior  end  of  the  inferior  turbinated  bone  will  guide  them  into  the 
middle  meatus,  wliicli  is  more  widely  open.     Foreign  bodies  are  most  frequently 


300  SURGICAL  ANATOMY. 

found  in   the   inferior   meatus.      If  these   bodies   are   retained  for  a   long  time, 
concretions  of  calcareous  matter  adhere  to  them  and  thus  rliinolUhs  are  formed. 

The  turbinated  bones  or  other  portions  of  the  walls  of  the  nasal  cavities  may 
be  the  site  of  necrosis,  which  causes  a  purulent  discharge  usually  from  one  nostril. 
The  carious  bone  should  be  removed,  and  wlien  the  disease  is  situated  high  uj), 
Rouge's  operation  offers  a  good  exposure  of  the  nasal  cavities.  In  this  operation 
the  upper  lip  is  everted,  and  the  tissues  of  the  lip  and  nose  are  detached  from 
the  external  surface  of  the  superior  maxilke. 

A    chronic   purulent   discharge   from    one    nostril    is   usually    caused    by    the 
presence  of  a  foreign  body  or  carious  bone  in  the  nasal  fossa  or  one  of  its  accessory     |i 
cavities  ;  and  from  Iioth  nostrils  by  constitutional  disease,  as  syjihilis. 

The  nasal  cavities  are  divided,  according  to  function,  into  the  olfactory 
portion,  Avhicli  includes  the  superior  meatus,  middle  turbinated  bone,  and  upper 
two-thirds  of  the  septum  of  the  nose,  and  the  respiratory  portion,  which  includes 
the  middle  meatus,  inferior  turbinated  bone,  inferior  meatus,  and  lower  one-third 
of  the  septum. 

The  nasal  cavities  are  lined  by  a  mucous  membrane  (Sehneiderian  or  pitui- 
tary membrane)  which  is  continuous  with  that  of  the  pharynx,  sphenoid  and 
ethmoid  cells,  frontal  sinuses,  antra  of  Highmore  or  maxillary  sinuses,  lacrymo- 
nasal  ducts,  and  lacrymal  sacs.  This  continuity  with  the  adjacent  mucous 
membrane  and  with  the  lining  of  the  acce.ssory  cavities  of  the  nose,  as  the  various 
air  sinuses  are  called,  is  very  im}iortant  to  remember,  for  there  is  a  marked  inter- 
relation existing  between  the  diseases  of  these  various  parts.  Empyema  of  the 
frontal  and  ethmoid  air  sinuses,  for  instance,  and  of  the  antrum  of  Highmore  is 
usually  dependent  upon  disease  of  the  nasal  mucosa.  In  the  olfactory  jjortion  the 
mucosa  is  of  a  yellowish  color,  which  gradually  fades  below,  making  no  marked 
line  between  the  mucous  menilirane  of  the  two  portions.  Over  the  nasal  septum 
it  is  rather  firmly  adherent  to  the  underlying  periosteum  ;  at  times  submucous 
hematomata  of  the  septum  are  seen  after  injury  of  the  nose.  On  the  anterior 
inferior  portion  of  the  septum  the  mucous  memln-ane  presents  a  little  diverticulum, 
which  is  the  remains  of  Jacobson's  organ.  This  organ  is  more  highly  developed 
in  the  lower  animals.  At  the  upper  two-thirds  of  the  septum  nnd  outer  Avail  (in 
tlic  olfiictory  portion)  the  mucous  membrane  is  delicate  and  thin,  ;iiid  contains  the 
])r,inc]u's  of  the  olfactory  nerve.  In  the  lower  or  respiratory  portion  of  tlie  nasal 
fo.ssa  (he  mucous  meml)r;in(:'is  tiiickei',  more  vascular,  and  jiale  red  in  color.  This 
is  especially  noticeable  over  the  lower  Ijorders  and  posterior  extremities  of  the 
middle  and  inferior  turbinated  liones,  where  it  is  soft  and  boggy  and  projects 
beyond  tlie  1)ones.  This  condition  is  due  to  the  presence  of  a  large  number  of 
V(.'ins  in  tlie  sul)nnicous  layer  of  the  nmcous  membrane  of  tlie  middle  and  inferior 


riTE  XOSE.  ;',01 

turl)inatoil  bones,  and  to  the  prestnu'o  ut'  fini'inous  spaces  of  erectile  ti88ue  in  tiiat 
of  tlie  inferior  tnrlnnatetl  bout'.  In  chronic  nasal  catarrh  these  cavernous  spaces 
arc  distended  with  blood,  the  nasal  cavity  is  occluded,  and  the  individual  is  unable 
to  breathe  through  the  nose.  The  mucous  membrane  of  the  anterior  extremity  of 
the  inft'rior  turl)inated  bone,  when  distended,  resembles  a  polypoid  growth. 

Instruments,  such  as  specula  or  tubes  of  atomizers,  introduced  through  the 
anterior  nares  should  be  directed  slightly  outward  to  avoid  striking  the  septum, 
which  causes  pain,  and  to  prevent  injury  to  the  mucous  membrane,  which  often 
bleeds  after  slight  traumatisms. 

Mucous  polypi  are  frequently  developed  in  the  nose,  and  usually  from  the 
nuicous  membrane  of  the  superior  or  middle  turbinated  bone  or  near  the  hiatus 
semilunaris.  They  occlude  the  nasal  cavity,  may  broaden  the  nose,  compressing 
the  nasal  ducts,  and  may  project  through  the  anterior  or  posterior  nares.  They 
should  be  removed,  and  if  the}'  continue  to  recur,  a  portion  of  the  adjacent 
bone  should  be  removed,  exercising  sufficient  care  to  avoid  fracturing  the  cribri- 
form plate  of  the  ethmoid  bone.  Fibrous  or  sarcomatous  polypi  arise  from  the 
periosteum  and  more  frequently  from  the  roof  of  the  nose. 

Bleeding  from  the  nose  (epistaxis)  is  one  of  tlie  prodromal  symptoms  of 
typhoid  fever,  but  it  is  more  commonly  due  to  other  causes,  such  as  engorged 
vessels,  as  in  plethoric  individuals,  or  ulceration  into  an  artery,  and  may  be  a 
symptom  of  fracture  of  the  base  of  the  skull,  purpura  hemorrhagica,  hemo- 
philia, scurvy,  or  ptomain  poisoning,  as  from  large  abscesses.  Hemorrhage  from  the 
nose  is  checked  by  the  laity  liy  pressure  on  the  upper  lip,  which  occludes  the  artery 
of  the  septum  ;  by  plugging  the  anterior  nares  ;  by  raising  the  arm  and  increasing 
the  expansion  of  the  chest,  which  lessens  the  pressure  in  the  veins  ;  and  by  drop- 
ping a  cold  key  down  the  back,  or  applying  cold  water  to  the  back  of  the  neck, 
and  thus  stimulating  the  vasomotor  nerves.  If  the  source  of  a  serious  hemorrhage 
can  not  be  found,  the  bleeding  can  be  checked  by  plugging  both  the  anterior  and 
posterior  nares,  which  is  done  by  introducing  a  strong  thread,  stilfened  by  soaking 
in  gum  and  drying,  into  the  nose  and  pharynx,  ami  bringing  it  out  through  the 
mouth  and  attaching  a  i)lug  of  cotton  to  it ;  or  a  soft  catheter  may  be  threaded 
and  carried  through  the  nose  into  the  pharynx.  One  end  of  the  thread  is  brought 
out  through  the  month  with  forceps,  and  the  other  through  the  nose  in  with- 
drawing the  catheter.  A  plug  of  cotton  the  size  of  a  walnut  is  then  attached 
to  the  string,  the  two  ends  of  which  are  tied  together  so  that  the  plug  can  be  pulk'd 
against  the  posterior  nares,  or  withdrawn  and  reapplied  if  necessary.  The  instru- 
ment specially  designed  for  plugging  the  posterior  nares  is  Bellocq's  cannula. 

Ozena  is  the  name  given  to  any  affection  of  the  nasal  fossae  giving  rise  to  a 
foul  discharge  from  the  nose.     A  fetid  purulent  discharge  from  both  nostrils  may 


302  SURGICAL  ANATOMY. 

be  a  symptom  of  atrophic  rhinitis,  syphilis,  carcinoma,  glandersj  or  occasionally 
necrosis ;  and  from  one  nostril  a  symptom  of  rhinoliths  (incrusted  foreign  bodies), 
necrosis,  or  emj^voma  of  one  of  the  accessory  cavities  of  the  nose. 

The  vestibule  of  the  nose  is  that  portion  of  the  nasal  fossa  -u-ithin  the  carti- 
laginous portion  of  the  nose,  and  is  lined  with  skin  which  blends  with  the  mucous 
membrane  of  the  nose. 

Tlie  mucous  glands  are  most  numerous  over  the  jiostcrior  portion  of  the 
outer  wall  and  septum  of  the  nose.  The  position  of  these  glands  and  the  backward 
and  downward  slope  of  the  nasal  floor  accounts  for  the  gravitation  of  the  mucus 
to  the  pharynx.  Occlusion  of  the  duct  of  a  mucous  gland  causes  the  formation 
of  a  retention  cyst. 

Some  lymphoid  tissue  is  also  found  in  the  nasal  mucous  membrane. 

Nerve  Supply. — The  nerve  supply  of  the  nasal  mucous  membrane  is  derived 
from  the  olfactory,  nasal,  and  naso-palatine  nerves,  branches  from  Meckel's 
ganglion  and  the  ^^idian  nerve,  branches  from  the  anterior  superior  dental  nerve, 
and  branches  from  the  anterior  palatine  nerve. 

The  olfactory  nerves,  which  arise  from  the  olfactory  bulb,  enter  the  nasal 
fossa  by  piercing  the  cribriform  plate  of  the  ethmoid  Iwne  as  numerous  branches. 
The  internal  or  mesial  l)ranches  ramify  u]>on  the  upper  one-third  of  the  septum, 
and  the  external  branches  upon  the  sujierior  turbinated  bones  and  the  surface  of 
the  ethmoid  above  and  in  front  of  these  bones.  They  form  plexuses  in  and 
beneath  the  mucous  membrane.  Anosmia,  or  loss  of  the  sense  of  smell,  after  a 
severe  blow  upon  the  head  is  supposed  to  Ije  due  to  rupture  of  the  olfactory  nerves 
where  thej^  pass  through  the  criliriform  plate. 

The  nasal  nerve  is  a  branch  of  the  ophthalmic  division  of  the  fifth  cranial 
nerve.  It  reaches  the  nasal  fossa  by  passing  through  the  slit  at  the  side  of  the 
crista  galli,  runs  downward  in  the  groove  on  the  internal  surface  of  the  nasal  bone, 
and  passes  forward  between  the  nasal  bone  and  the  upper  lateral  cartilage  to  sup- 
ply the  tip  of  the  nose.  It  supplies  branches  to  the  anterior  portion  of  both  the 
outer  wall  and  the  septum  of  the  nose. 

The  naso-palatine  nerve  is  a  branch  of  IMeckel's  ganglion,  and  enters  the 
nasal  fossa  with  the  naso-palatine  artery  at  the  spheno-palatine  foramen.  It  crosses 
on  the  body  of  the  sphenoid  bone  to  the  septum,  upon  which  it  runs  downward  and 
forward,  supplying  its  middle  portion. 

The  branches  from  the  Vidian  nerve  and  the  anterior  l)ranclies  of  Meckel's 
ganglion  ai'e  small.  They  supply  the  ujtper  and  back  part  of  the  septum  and  the 
superior  tuvliinntcd  bone.     They  can  seldom  be  traced. 

The  branches  of  the  anterior  superior  dental  branch  of  the  superior  maxil- 
lary nerve  supply  the  inferior  turbinated  bone    and    the    inferior   meatus.     The 


PLATE  LXXII 


Nasal  n. 


Olfactory  n. 

Olfactory  tract 


Superior  nasal  nerves 
Spheno-palatine  n. 


Naso-palatine  n 


Great  palatine  n 
External  palatine  n 

Posterior  palatine  n 

Tensor  palati  m 
Internal  pterygoid  m 

Otic  ganglion 
Sympathetic  root  of  otic  gang 

Middle  nneningeal  aJ 
Auriculo-temporal  n 


OLFACTORY  NERVES. 
303 


11—20 


PLATE  LXXIIl, 


Nasal  septum 


Anterior  nasai  spine 


Middle  turbinal 


-Inferior  turbinal 


ANTERIOR  VIEW  OF  NASAL  F08S/E. 
30G 


THE  NOSE.  307 

branches  from  the  anterior  palatine  nerve  (inferior  nasal  nerves)  run  forward  upon 
tlie  middle  and  inferior  turbinated  bones. 

Bi.ooD  Suri'LY. — The  blood  supply  of  the  nasal  cavities  is  derived  from  the 
spheno-palatine,  descending  palatine,  anterior  and  posterior  ethmoid  arteries, 
and  tlu'  artery  of  the  septum. 

Tlie  spheno-palatine  artery,  a  branch  of  the  internal  maxillary,  is  the  prin- 
cipal artery  of  the  nasal  fossa.  It  enters  it  at  the  spheno-])alatine  foramen  with  the 
naso-palatine  nerve.  Its  internal  branch,  the  naso-palatine,  accompanies  the  naso- 
palatine nerve  downward  and  forward  upon  the  septum  toward  the  anterior  pala- 
tine foramen.  Its  external  Ijranches  supply  the  outer  wall  of  the  cavity,  the 
ethmoid  cells,  frontal  sinus,  and  antrum  of  Highmore. 

The  descending  palatine  artery  is  also  a  branch  of  the  internal  maxillary 
artery.  It  gives  otf  a  few  small  In'anchcs  to  the  posterior  portion  of  the  outer  wall 
of  the  nasal  fossa. 

The  anterior  and  posterior  ethmoid  arteries  are  branches  of  the  ophthal- 
mic artery.  They  supply  the  roof,  upper  portion  of  the  septum,  and  outer  wall 
of  the  nasal  fossa,  ethmoid  cells,  and  frontal  sinuses. 

The  artery  of  the  septum  is  derived  fi-om  the  superior  coronary  branch  of 
the  facial  artery.     It  supplies  the  eolumna  and  the  lower  portion  of  the  septum. 

The  veins  of  the  nasal  cavities  form  a  plexus  under  the  mucous  membrane. 
The  plexus  is  drained  l)y  the  veins  which  accompany  the  spheno-palatine  artery 
and  empty  into  the  pterygoiil  plexus ;  those  which  follow  the  ethmoid  arteries 
and  empty  into  the  ophthalmic  vein  ;  some  which  pass  througli  tlie  foramina  in 
the  nasal  bone  and  nasal  process  of  the  superior  maxilla  to  empty  into  the  facial 
vein ;  and  others  which  pass  through  the  foramen  caecum  to  join  the  superior 
longitudinal  sinus  and  through  the  cribriform  plate  of  the  ethmoid  bone  to  join 
the  intra-cranial  veins. 

The  lymphatic  vessels  of  the  muco-periosteal  lining  and  walls  of  the  nasal 
fossaj  terminate  in  the  post-pharyngeal  lymphatic  gland,  the  internal  maxillary 
lymphatic  glands,  the  parotid  lymphatic  glands,  and  the  superior  deep  cervical 
lymphatic  glands.  Through  the  cribriform  plate  of  the  ethmoid  bone  these 
vessels  communicate  with  the  intra-cranial  lymphatics  and  the  subdural  space, 
affording  a  channel  through  which  meningitis  may  be  produced  by  caries  of  the 
upper  portion  of  the  wall  of  the  nose.  Involvement  of  the  posf-]iharyngeal, 
internal  maxillary,  parotid,  and  superior  deep  cervical  lymphatic  glands  may 
also  result  from  disease  of  the  nasal  fossfe. 

In  anterior  rhinoscopy,  or  examination  of  the  nasal  fossa  through  the  ante- 
rior naris,  tlie  following  structures  can  be  observed :  The  septum,  which  should 
occupy  a  vertical  position,  and,  if  it  deviates  toward  the  fossa  under  examination,  it 


308  SURGICAL  ANATOMY. 

should  not  be  mistaken  for  a  tumor ;  the  floor  of  the  nose  ;  the  inferior  turbinated 
bone,  which  extends  backward  along  the  outer  wall  of  the  fossa ;  the  middle 
meatus ;  the  middle  turbinated  bone ;  and  high  up  the  superior  meatus  and  the 
anterior  extremity  of  the  superior  turbinated  bone. 

Posterior  rhinoscopy,  or  examination  of  the  nasal  fossse  through  the  posterior 
nares  is  quite  difficult,  and  can  be  performed  only  after  some  practice.  A  small 
mirror,  similar  to  a  laryngoscopic  mirror,  is  inserted  behind  the  soft  palate,  while 
the  patient  breathes  through  the  nose  and  the  tongue  is  depressed  by  the 
examiner.  By  means  of  light  reflected  through  the  mouth  the  following  structures 
can  be  seen :  The  jjosterior  nares,  separated  bj^  the  posterior  margin  of  the  nasal 
septum ;  the  upper  or  attached  portion  of  tlie  inferior  turbinated  l)one ;  the 
middle  meatus ;  the  middle  turbinated  bone ;  the  superior  meatus ;  the  superior 
turbinated  bone  ;  the  roof  of  the  naso-pharynx  ;  the  upper  part  of  the  j^osterior 
wall  of  the  naso-pharynx  ;  the  pharyngeal  tonsil ;  the  upper  part  of  the  lateral 
wall  of  the  naso-pharynx  ;  the  pharyngeal  recess ;  and  the  profile  of  the  trumpet- 
shaped  orifice  of  the  Eustachian  tube. 

Nasal  douche. — In  nasal  catarrh  the  nasal  fossae  are  frequently  cleansed  by 
spraying  or  douching  with  an  alkaline  solution.  In  using  the  nasal  douche  the 
solution  flows  in  one  anterior  naris  and  out  through  the  other,  elevation  of  the  soft 
palate  against  the  posterior  wall  of  the  pharynx  preventing  the  solution  from 
passing  into  the  ovo-pharynx.  The  bottom  of  the  vessel  containing  the  solution 
should  not  be  placed  above  the  level  of  the  eyebrows,  and  the  head  should  be 
inclined  slightly  forward  so  that  the  solution  will  not  enter  the  Eustachian  tubes, 
the  orifices  of  which  are  on  a  level  with  the  posterior  extremities  of  the  inferior 
turbinated  bones.  If  the  solution  should  enter  the  middle  ear  through  the 
Eustachian  tube,  otitis  media  and  deafness  might  resvilt. 

Dissection. — The  student  should  now  turn  the  superior  turbinated  bone 
upward,  and  with  a  probe  search  for  the  orifices  of  the  sphenoid  sinus  and  poste- 
rior ethmoid  cells ;  remove  the  anterior  portion  of  the  middle  turbinated  bone,  to 
find  the  orifices  of  the  antrum  of  Highmore,  anterior  ethmoid  cells,  and  the  in- 
fundibulum,  and  cut  away  the  anterior  portion  of  the  inferior  turbinated  bone  to  see 
the  inferior  opening  of  the  lacrymo-nasal  duct.  The  frontal  and  sphenoid  sinuses 
have  been  opened  in  sawing  through  the  skull,  so  they  can  be  satisfactorily  studied. 

The  frontal  sinuses  are  situated  between  the  inner  and  outer  tables  of  the 
frontal  bones,  at  the  position  of  the  superciliary  eminences  and  glabella.  They  are 
aljsent  before  the  seventh  year,  when  they  originate  as  extensions  of  the  anterior 
ethmoid  cells,  and  reach  their  full  development  at  about  the  twentieth  year. 
The  anterior  or  external  bony  wall  of  the  sinuses  is  the  thicker  of  the  two,  and, 
upon  careful  examination,  it  can  usually  l)o  seen  to  consist  of  two  lamiiiir,  between 


PLATE  LXXIV. 


Sphenoid  cells 


Apex  of  orbit 


Midd 


dum 


POSTERIOR  VIEW  OF  NASAL  FOSS/E. 
309 


THK  ^•OSI':.  ;]  1 1 

which  there  is  ;i  lliiii  ili|ihiic  layer.  Tlie  weakest  and  thinnest  i)()rti<in  of  this 
external  wall  is  just  ahuve  the  inner  an^ie  (if  the  orhit,  and  when  a  enlleetion  of 
pus  in  the  frontal  sinus  hursts  externally,  it  is  u.sually  at  this  point  that  the  open- 
ing occurs.  Sueh  a  fistulous  openin,i;-  may  he  mistaken  In' the  careless  ohserver 
for  a  fistula  laehrymalis. 

The  h'onlal  siniises  are  extremely  variahle  in  size  and  form.  A  thin  osseous 
partition  usually  sc.'parates  one  sinus  h-om  the  other;  this  septum  may,  however, 
he  ineompleh'.  In  many  eases  these  sinuses  extend  haekwai'd  for  a  considerable 
<listance  over  the  roof  of  the  orbit.  Additional  septa  may  divide  the  cavity  into 
subcompartnients,  and,  furthermoi-e,  one  or  two  of  the  ethmoid  cells  may  bulge 
into  the  sinus.  In  women  they  are  comparatively  small.  In  some  individuals 
they  are  quite  small,  or  even  absent,  and  this  is  said  to  be  the  common  condition 
in  skulls  \\hieh  have  a  miilfrontal  suture.  Tluy  open  into  the  middle  meatuses 
of  the  nasal  fosste  by  means  of  the  infundibula.  They  are  lined  by  mucous 
membrane,  which  is  an  extension  of  that  of  the  nose  and  is  supplied  by  filaments 
of  the  nasal  nerve. 

Congestion  of  the  rnncons  nnnibrave  of  the  frontal  si)niMcs,  which  is  likely  to  be 
associated  with  acute  corvza,  or  "cold  in  the  head,"  jiroduces  the  dull  ache  over 
the  glal)ella  and  suiterciliary  eminences  in  tliat  affection.  "When  drainage  from 
the  sinuses  is  insufficient,  mucus  becomes  inspissated  within  them. 

Empyema,  or  a  purulent  collection  in  the  frontal  sinus,  is  often  associated  with 
occlusion  of  the  infundibulum,  and,  because  of  the  unyielding  character  of  the 
walls  of  the  sinus,  causes  much  pain.  If  the  infundibulum  is  patulous,  the  pus 
appears  in  the  middle  meatus  of  the  nose.  For  tlie  proper  treatment  of  this 
affection  it  is  necessary  to  trephine  the  anterior  wall  of  the  sinus,  reestablish  the 
communication  with  the  nose,  and  in.stitute  drainage  by  means  of  a  tube  pas.sed 
into  the  nasal  fossa.  The  incision  is  made  just  below  the  supra-orbital  margin, 
and  extends  from  the  root  of  the  nose  outward  for  about  an  inch.  A  small 
trephine  or  a  drill  is  applied  just  above  the  inner  angle  of  the  orbit,  where  the 
bone  is  thin. 

The  external  table  of  the  skull  may  he  fractured  and  depressed  at  the  position  of 
the  frontal  sinuses  without  injuring  the  inner  table  or  affecting  the  cranial  contents, 
and  the  inspLssated  mucus  escaping  from  the  sinus  may  be  mistaken  for  brain 
matter.  These  fractures  are  often  accompanied  by  emphysema,  in  wliich  case  the 
air  is  derived  from  the  nose  by  way  of  the  infundibulum. 

Living  foreign  bodies,  such  as  centipedes,  maggots,  and  insects,  maj'  enter  the 
frontal  .sinuses  by  passing  up  the  infundibulum. 

A  polypus  is  sometimes  found  in  one  of  the  frontal  sinuses.  It  may  originate 
in  the  sinus  or  in  the  nose,  and  enter  the  sinus  by  way  of  the  infundibulum.     If  it 


312  SURGICAL  ANATOMY. 

continues  to  enlarge,  it  may  bulge  the  anterior  wall  or  orbital  wall  of  the  sinus 
and  displace  the  eyeball.  It  can  be  removed  by  trephining  the  anterior  wall  of 
the  sinus. 

Dissection. — The  antrum  of  Highmore,  or  maxillary  sinus,  should  be  opened 
by  sawing  away  part  of  its  external  wall. 

The  antrum  of  Highmore,  or  maxillary  sinus,  is  an  accessory  air  chamber  of 
the  nose,  and  is  situated  in  the  superior  maxillary  bone.  It  is  irregularly  pyram- 
idal in  shape,  the  base  of  the  pyramid  being  directed  toward  the  nose,  and  the 
apex  toward  the  malar  process  of  the  sujierior  maxilla.  The  base  is  formed  by  the 
external  wall  of  the  nasal  fossa — i.  e.,  by  the  nasal  surface  of  the  superior  maxilla, 
the  maxillary  jjrocess  of  the  inferior  turbinated  bone,  the  uncinate  process  of  the 
ethmoid  bone,  the  vertical  plate  of  the  palate  bone,  and  the  lacrymal  bone.  In 
the  upper  and  posterior  part  of  this  surface  is  the  orifice  of  the  sinus,  which  is  so 
situated  that  drainage  from  the  antrum  is  defective.  Consequentlj',  mucus  or  pus 
may  be  retained  in  the  cavitj',  forming  a  mucocele  or  empyema  of  the  antmm. 
The  roof  of  the  antrum  is  formed  by  the  orbital  plate  of  the  superior  maxilla,  the 
floor  by  the  alveolar  process  of  the  superior  maxilla,  the  anterior  or  external 
wall  by  the  facial  surface  of  the  superior  maxilla,  and  the  posterior  wall  by  the 
zygomatic  surface  of  the  superior  maxilla. 

The  antrum  is  usually  larger  in  the  male  than  in  the  female.  In  young 
subjects  the  antrum  is  small  and  its  walls  are  c[uite  thick  ;  absorptive  processes  in 
old  age  may  cause  a  defect  in  the  anterior  bony  wall.  The  two  antra  are  fre- 
quentl}'  asymmetric  in  size  and  shape.  The  roots  of  the  first  and  second  molar 
teeth  often,  and  those  of  the  j^remolars  and  canine  teeth  occasionally,  form  promi- 
nences in  the  floor  of  the  cavity.  It  is  evident  that  caries  of  these  teeth  and  their 
fangs  may  lead  to  antral  disease. 

The  mucous  membrane  of  the  maxillary  sinus  is  thinner  and  less  vascular  than 
that  of  the  nasal  fossa. 

The  orifice  of  the  antrum  opens  into  the  lower  part  of  the  hiatus  semilunaris 
and  the  middle  meatus  of  the  nose.  The  orifice  is  small  and  rounded  or  elliptic. 
In  cinjiyema  and  mucocele  of  the  antrum  the  orifice  is  usually  closed  by  thicken- 
ing of  the  mucous  membrane  of  the  nose  in  rhinitis.  Tliere  may  be  one  or  more 
additional  orifices  leading  into  the  nasal  fossa. 

The  tumors  which  originate  in  the  antrum  may  be  either  malignant  or  benign. 
By  pressure  ujion  the  M'alls  of  the  sinus  they  encroach  upon  the  orbital  and  nasal 
fossce,  lacrymal  duct,  ]itorvgo-maxillary  ri'gion,  and  mouth,  and  rausc  Imlging  of 
the  cheek.     Tlie  malignant  tumors  are  removed  by  excising  tlic  superior  maxilla. 

Empyema,  or  abscess  of  the  antrum,  may  be  caused  by  extension  of  catarrh 
from   the  nose  to   the   antrum,  with   occlusion   of  the  antral  orifice,  retention  of 


PLATE  LXXV. 


Frontal  sinus 

Straw  in  infundibulum 

Orifices  of  anterior  ethmoidal  cells 
Bulla  ethmoidalis 

Drifices  of  posterior  ethmoidal  cells  in   superior  meatus 
Superior  turbinal  (cut) 

Straw  in  orifice  of  sphenoidal  cell 
Sphenoidal,  cell 

Diaphragma  sellae 
Cavum  sellae 


Middle  turbinal  (cut) 


Orifice  of  Eustachian  tube 


Hiatus  semilunaris 


Inferior  meatus 
Inferior  turbinal 
Middle  meatus 
Middle  turbinal  (cut) 
Straw  in  orifice  of  Antrumof  Highmore 
Additional  orifice  of  Antrum  of  Highmore 
Straw  in  nasal  duct 


ORIFICES  OF  NASAL  DUCT  AND  ACCESSORY  AIR-CHAMBERS  OF  NOSE. 

314 


THE  NOSE.  31.5 

mucus,  and  f(irmation  of  pus  ;  by  diseased  fangs  of  teeth  projecting  into  the  cavity  ; 
])}•  fevers,  as  scarlet  fever;  and  by  injury.  If  the  orifice  of  the  antrum  is  not 
occkidcd,  the  pus  may  escape  into  the  middle  meatus  by  overflowing,  whicli  is 
favored  by  lying  upon  a  horizontal  surface  ^vith  the  opposite  side  of  the  face  resting 
uj)on  that  surface.  If  tlir  oi-itiee  is  closed,  it  will  be  necessary  to  drain  the  antrum 
by  extracting  a  carious  l)ieuspiil  or  molar  tooth  which  may  cause  the  absces.?, 
and  forcing  a  trocar  through  the  alveolus  into  the  antrum.  If  the  teeth  are  not 
diseased,  the  sinus  may  be  opened  by  everting  the  upper  \i\)  and  drilling  or 
trephining  the  canine  fossa  just  above  the  second  bicusjjid  tooth,  or  by  drilling  the 
nasal  wall  of  the  cavitj'  in  the  middle  or  inferior  meatus  of  the  no.se. 

In  dropsy  of  the  nntriirii,  or  liydroi)s  antri,  a  glairy  or  thin  serous  fluid  occupies 
the  maxillary  sinus.     It  arises  from  cj^stio  degeneration  of  the  mucous  membrane. 

Dcntigerous  cysts  of  the  antrum  arise  through  abnormal  development  of  a  tooth, 
which  may  be  caused  by  failure  to  lose  one  of  the  temporary  teeth. 

The  ethmoid  sinuses  or  cells  are  situated  in  tlie  lateral  masses  of  the  eth- 
moid bone.  On  each  siile  they  are  divided  into  two  sets — an  anterior  and  a 
po.sterior.  The  anterior  set  forms  a  rounded  eminence,  the  bulla  ethmoidalis,  situ- 
ated in  the  outer  wall  of  the  nasal  fossa  just  above  the  hiatus  semilunaris,  into 
which  many  of  the  cells  open.  The  remaining  anterior  ethmoid  cells  open 
directly  into  the  middle  meatus  of  the  nose.  The  posterior  ethmoid  cells  open 
into  the  superior  meatus  of  the  nose.  The  ethmoid  cells  are  lined  by  muco- 
periosteum  continuous  Avith  that  of  the  nasal  fo.ssa,  and  may  be  affected  by 
catarrhal  inflammation  extending  from  the  no.se,  by  necrosis,  mucocele,  or  malig- 
nant or  benign  growths. 

The  sphenoid  sinuses  or  cells  are  located  in  the  body  of  the  sphenoid  bone. 
The}-  are  usually  two  in  immber,  being  separated  by  a  delicate  septum.  They  are 
lined  by  muco-periosteum  continuous  with  that  of  the  nose  and  roof  of  the 
pharynx.  Their  orifices  are  situated  in  the  pcsterior  part  of  the  roof  of  the  nose, 
opposite  the  posterior  extremity  of  the  superior  turbinated  bone,  and  are  said  to 
open  into  the  superior  meatus  of  the  nose.  They  may  be  the  site  of  catarrh  and 
malignant  or  benign  growths. 

Dissection. — The  .student  should  now  remove  the  mucous  membrane  from 
the  septum  and  the  outer  wall  of  the  nose,  and  trace  the  vessels  and  nerves  pre- 
viously described.  If  the  otic  ganglion  has  not  been  destroyed  and  tlie  part  is  in 
good  condition,  the  ganglion  may  be  seen  by  carefully  removing  the  cartilaginous 
portion  of  the  Eustachian  tube  and  tracing  upward  the  nerve  .to  the  internal 
pterygoid  muscle.  The  ganglion  will  be  found  on  tlie  inner  side  of  the  inferior 
maxillary  nerve,  below  the  foramen  ovale.  For  description  of  the  otic  ganglion, 
see  volume  i,  page  555. 


316  SURGICAL  ANATOMY. 

THE  ORBIT. 

The  Orbits  are  two  irregularlj^  conic  or  pyramidal  cavities  which  contain  the 
ej'eballs  and  their  accessory  structures — muscles,  vessels,  nerves,  and  fat.  The 
walls  of  each  orbit  are  lined  with  a  loosely  attached  periosteum  or  periorbita. 
The  orbit  has  an  apex,  a  base,  and  four  walls. 

The  apex  of  the  orbit  is  directed  backward,  and  is  situated  at  the  optic 
foramen,  through  which  the  optic  nerve  and  ophthalmic  artery  enter  the  orbit. 

The  base  of  the  orbit  is  directed  outward  and  forward,  and  is  the  onlj'  wall 
of  this  cavity  which  is  absent  or  not  filled  by  bone.  The  margins  of  the  base  are  : 
above,  the  supra-orbital  margin  ;  below,  the  infra-orbital  margin.  They  project 
beyond  the  eyeball  and  protect  it  from  injury  hy  blows  from  large  objects.  The 
oi'bital  margins  are  formed  above  by  the  frontal  bone ;  externally,  by  the  malar 
bone  ;  internally,  by  the  nasal  process  of  the  superior  maxilla  ;  below,  l>y  the  malar 
bone  and  the  body  of  the  superior  maxilla.  The  supra-orbital  margin  contains 
the  supra-orbital  notch — a  landmark  in  operations  upon  the  supra-orbital  and 
infra-orbital  nerves.  This  notch  is  situated  at  the  junction  of  the  inner  one-third 
^\•ith  the  outer  two-thirds  of  that  margin,  and  transmits  the  supra-orbital  vessels 
and  nerves. 

The  roof  of  the  orbit  is  formed  by  the  orbital  plate  of  the  frontal  bone  and 
the  lesser  wing  of  the  sphenoid  bone.  The  frontal  sinuses  frequently  project 
backward  into  that  part  of  the  orbital  roof  formed  by  the  frontal  bone ;  conse- 
quently tumors  or  an  empyema  of  the  frontal  sinus  may  encroach  upon  the  orbit 
and  cause  displacement  of  the  eyeball  and  double  vision — diplopia.  At  the  outer 
side,  near  the  base  of  the  orbit,  the  roof  presents  a  large  depression — the  lacrymal 
fossa — for  the  lacrymal  gland  ;  and  at  the  inner  side,  near  the  base  of  the  orbit, 
the  small  depression  to  which  the  pulley  of  the  superior  oblique  muscle  is  attached. 
On  account  of  the  relation  between  the  orbit  and  the  cranial  cavity  and  the 
tenuity  of  the  intervening  bony  wall,  a  foreign  body  with  a  sharp  point,  such  as  a 
foil  or  .stick,  may  enter  the  orbit,  pierce  the  roof  of  that  cavity,  and  penetrate  the 
brain  without  producing  an  apparently'  grave  external  injury. 

The  floor  of  the  orbit  is  formed  by  the  superior  maxilla,  the  malar  bone,  and 
the  orbital  plate  of  the  palate  bone.  Beneath  the  greater  portion  of  the  floor  is 
the  antrum  of  Highmore,  tumors  of  which  may  encroach  upon  the  orbit,  displace 
the  eyeball,  niid  cause  diplopia. 

Tlif  outer  wall  of  the  orbit  inclines  obliquely  forward  and  outward,  and  is 
formed  by  the  malar  bone,  the  external  angular  process  of  the  frontal  bone,  and 
the  greater  Ming  of  the  sphenoid  bone.  When  dividing  the  optic  nerve  in 
excision  of  the  eyeball,  the  scissors  is  more  readily  introduced  on  the  outer  side, 


THE  ORBIT.  317 

because  of  the  greater  space  between  the  eyeball  and  the  outer  wall  and  the  out- 
ward slope  of  that  wall,  which  makes  a  larger  angle  with  the  optic  nerve  than 
does  the  inner  wall. 

The  inner  wall  of  the  orbit  is  tbrnud  liy  the  nasal  process  of  the  sujierior 
maxilla,  tiu'  intcnial  angular  process  of  the  frontal  bone,  the  lacrymal  bone,  the  os 
planum  of  the  ethmoid  bone,  and  the  body  of  the  Sfihenoid  bone.  Near  the  base 
of  the  orbit  the  inner  wall  presents  a  large  depression — the  lacrymal  groove — 
which  lodges  the  lacrymal  sac  and  below  leads  into  the  lacrymal  canal,  which  is 
lined  by  the  muco-periosteal  wall  of  the  lacrymo-nasal  duct.  In  the  inner  wall 
of  the  orbit,  and  sei)arated  from  that  cavity  by  a  tliin  bony  jiartition,  are  the 
ethmoid  cells  and  the  sphenoid  cell  or  sinus.  Tumors,  empyema,  or  mucocele 
of  these  cells  may  encroach  upon  the  orbit,  displace  the  ej'eball,  and  cause 
diplopia. 

Measurements. — The  antero-jjosterior  diameter  of  the  orbit  is  about  one  and 
three-fourth  inches.  At  the  base  the  vertical  diameter  is  about  one  and  one- 
fourth  inches,  and  the  transverse  diameter  about  one  and  one-half  inches. 

The  orbit  is  widely  open  anteriorly,  and  posteriorly  it  is  in  comnnuiication 
with  the  cranial  cavity  through  the  optic  foramen  and  the  sphenoid  fissure,  and 
with  the  pterygo-maxillary  region  and  spheno-maxillary  fossa  through  the  spheno- 
maxillary fissure. 

Blood  may  be  extravasated  into  the  orbit  after  fracture  of  one  of  the  -^^-alls  of 
that  cavity,  more  commonly  the  roof.  Tumors,  blood,  or  pus  may  enter  the  orbit 
from  the  pterygo-maxillary  region  through  the  spheno-maxillary  fissure,  and  from 
the  cranial  cavity  through  the  sphenoid  fissure.  Blood  extravasated  into  the  orbit 
produces  subconjunctival  ecchymosis. 

Dissection. — According  to  the  level  at  which  the  calvaria  has  been 
removed,  there  will  be  found  remaining  more  or  less  of  the  vertical  plate  of  the 
frontal  bone,  covered  in  front  by  the  soft  parts.  Tlie  soft  tissues  should  be  turned 
down  after  making  two  incisions  down  to  the  bone,  one  running  vertically  upward 
from  the  nasion  and  the  other  running  parallel  to  the  vertical  incision,  and  start- 
ing from  the  external  angular  process  of  the  frontal  bone.  Should  there  be  much 
of  the  vertical  plate  of  the  frontal  bone  remaining,  it  should  be  removed  with 
hammer  and  chisel  almo.st  as  far  down  as  the  supra-orbital  arch.  The  roof  of  the 
orbit  should  now  be  removed,  either  entirely  or  all  of  it  except  the  sui)ra-orbital 
margin,  as  suggested  by  Cunningham.  In  the  former  method  two  cuts,  converg- 
ing at  the  optic  foramen,  are  made  with  a  saw,  leaving  the  bone  around  the  optic 
foramen  undisturbed,  and  then,  by  a  firm  tap  with  a  mallet,  breaking  away  the 
orbital  roof,  and  turning  it  forward.  In  Cunningham's  method  the  thin  ])late  of 
bone  covering  the  orbit  is  removed  with  a  chisel  and  mallet,  leaving  intact  the 


318  SURGICAL  AXATOMY. 

ring  of  bone  around  the  optic  foramen  and  tliat  constituting  the  supra-orbital 
margin.  Care  should  be  taken  to  avoid  injuring  two  structures — tlie  pulley  of  the 
superior  oblique  muscle  and  the  orbital  periosteum. 

If  at  the  time  the  dissection  of  this  portion  of  the  bodj-  is  begun  the  eyeball 
has  collapsed,  it  .should  be  inflated.  After  the  periosteum  has  been  opened,  carry 
a  ligature  loosely  around  the  ojjtic  nerve  1)y  means  of  an  aneurysm  needle ;  then 
insert  a  blowpipe  between  the  optic  nerve  and  its  sheath,  thrusting  it  almost,  if 
not  quite,  into  the  eyeball.  Inflate  until  the  ball  is  tense ;  then,  wliile  an 
assistant  is  slowly  withdrawing  the  blowpipe,  draw  the  ligature  tight. 

The  eyeball  is  preferably  inflated  from  the  front,  this  procedure  being  less 
difficult,  more  successful,  and  allowing  rcinflation  when  necessary.  In  this  method 
a  sharp  needle  is  introduced  obli(iuely  at  the  sclei'o-corneal  junction.  The  blow- 
pipe is  then  inserted  through  the  puncture,  and,  after  the  eyeball  is  distended, 
withdrawn.  The  valvular  character  of  the  incision  is  sufficient  to  prevent  rapid 
escape  of  the  air. 

Orbital  Periosteum  or  Periorbita. — Tlie  orbital  roof  having  been  removed, 
the  perio.steum  comes  into  view.  It  incloses  the  structures  which  fill  the  orbit, 
and  is  but  loosely  attached  to  the  bony  walls.  It  is  continuous  posteriorly  with 
the  endosteal  layer  of  the  dura  mater  through  the  optic  foramen  and  the  sphenoid 
fissure.  Anteriorly  the  periorbita  divides  at  the  orbital  margins  into  two  lamellse 
— one  is  continuous  with  the  periosteum  on  the  facial  surface  of  the  bones  which 
form  those  margins,  and  the  other  blends  with  the  palpebral  fascia  of  the  eyelids. 

Dissection. — Two  incisions  are  now  made  through  the  periosteum.  One  is 
transverse,  and  runs  parallel  to  the  supra-orbital  ridge ;  the  other  is  longitudinal, 
and  runs  antero-posteriorlj'  from  the  optic  foramen  to  the  middle  of  the  first  inci- 
sion. Either  a  very  sliai'p  knife  must  be  used,  or  else  a  nick  should  be  made  in 
the  periosteum  and  the  rest  of  the  cutting  done  with  scissors  or  with  a  knife  in  the 
trough  of  a  small  grooved  director.  The  two  flaps  thus  formed  should  be  carefully 
turned  aside,  gently  separating  them  from  the  underlying  structures.  Further 
dissection  is  much  facilitated  liy  drawing  forward  the  eyeball  and  retaining  it  in 
position  witli  a  suture  or  hooks,  taking  care  not  to  puncture  the  eyeball,  and 
allow  tlie  escape  of  its  contained  air. 

Structures  Exposed  by  Removal  of  the  Periosteum. — The  orbital  fat,  orbital 
fascia,  and  IVontal  nerve  are  exposed  as  soon  as  the  flaps  of  periosteum  are 
reflected.  Careful  removal  of  .some  of  the  orliital  fat  will  demonstrate  a  number 
of  structures. 

In  tlie  median  line  the  frontal  nerve  is  I'cadily  demonstrable  without  dissec- 
tion. It  lies  upon  the  levator  ])ali)el)r[e  su]ierioris  muscle,  and  its  anterior  portion 
is  accomjianied  by  tlu'  supra-nrbilal  artery. 


PLATE  LXXVl, 


Orbital  fascia 
Capsula  of  Tenon 
Fat 
Superior  rectus  m, 
Levator  palpebrae 
superioris  m. 


Connection  between  superior  rectus  m. 
and  levator  palpebrae   superioris  m. 

Capsule  of  Tenon 

Fornix  conjunctivae 

Septum  orbitale  or 
orhito-tarsal  lig. 


Check  lig'  of  inferior  rectus  m. 
blique  m 


Optic  n, 
Capsule  of  Tenon 


Orbital  fascia 


ORBITAL  FASCIA  AND  CAPSULE  OF  TENON-SACITTAL  SECTION. 

320 


PLATE  LXXVII 


Orbicularis  palpebrarum  m. 


Ethmoid  cells 

Orbital  fascia  envel 
internal 


Supravaginal  lymph  space 


Temporal  m. 
of  cranial  cavity. 


J  Tenon's  space 


11-31 


ORBITAL  FASCIA  AND  CAPSULE  OF  TENON-TRANSVERSE  SECTION. 

321 


rilE   on  BIT.  323 

Running  along  the  outer  wall  of  tlie  orbit,  an<l  just  above  the  external  rectus 
muscle,  will  be  seen  the  laerymal  nerve  and  artery. 

At  the  front  and  outer  \n\vi  of  the  orbit  the  laerymal  gland  appears  resting 
against  the  laerymal  fossa  in  the  under  surface  of  the  horizontal  plate  of  the 
frontal  bone. 

Along  the  inner  wall  will  bo  seen  the  superior  oblique  muscle.  At  its  anterior 
portion  the  fibrous  ring  or  pulky  tliniugh  which  its  tendon  works  can  Ik;  demon- 
strated ;  and,  well  back  in  its  courst",  the  fourth  or  pathetic  .nerve  will  be  seen 
entering  its  fleshy  portion. 

The  orbital  fat. — The  posterior  half  of  the  orbit  contains  a  large  mass  of 
stringy,  coherent  fat,  which  forms  a  soft  pad  or  cushion  for  the  support  of  the  eye- 
ball, and  fills  the  interstices  between  the  muscles,  vessels,  and  nerves.  The  sink- 
ing in  of  the  eyeball,  coincident  with  the  emaciation  of  disease  or  age,  is  due  to 
partial  absorption  of  this  fat. 

Orbital  abscesses  are  situated  in  the  orbital  fat  and  may  develop  therein  ;  they 
may  arise  from  ocular  inflammation,  periostitis,  injuries,  or  result  from  extension 
from  adjacent  cavities,  as  the  ethmoid  or  sphenoid  cells,  antrum  of  Ilighmore, 
pterygo-maxillarj'  region,  or  cranial  cavity.  If  the  absce.ss  attains  a  large  size,  it 
displaces  the  ej'eball  forward,  retards  its  movements,  and,  through  pressure  upon 
the  ophthalmic  vein  and  its  tributaries,  causes  congestion  of  the  conjunctiva  and 
swelling  of  the  eyelids. 

Foreign  bodies  may  lodge  in  the  orbital  fat  for  a  long  time  without  causing 
much  disturbance. 

Ei)iplnjscma  of  the  orbit,  or  aii'  in  the  orbital  fat,  results  from  rupture  of  the 
orbital  periosteum  and  fracture  of  the  wall  intervening  between  the  orbit  and  one 
of  the  accessory  air-chambers  of  the  nose — viz.,  the  frontal  sinuses,  ethmoid  cells, 
sphenoid  cells,  and  antrum  of  Highmore. 

The  orbital  fascia  resembles  the  deep  fascia  of  other  locations.  It  envelops 
and  forms  sheaths  for  the  nui.scles,  vessels,  and  nerves  of  the  orbit,  and  .sends 
partitions  or  septa  into  the  orbital  fat  which  separate  it  into  lobules.  Posteriorly, 
or  at  the  apex  of  the  orbit,  the  oi-bital  fascia  is  continuous  with  the  orbital 
periosteum  around  the  origins  of  the  nuisclos.  It  passes  forward  as  a  single  layer 
between  the  muscles,  and  wliere  each  of  the  mu.scles  is  located  it  exists  as  two 
layers  which  envelop  the  muscle.  Near  the  apex  of  the  orbit  it  is  thin  and  la.x, 
but  as  it  passes  forward  it  l)ecomes  nuicli  stronger  and  more  adherent  to  the 
muscles.  Al)out  opposite  the  equator  of  the  eyeball  it  divides  into  two  lamina' — 
the  anterior  and  the  posterior.  The  anterior  lamina  of  the  orbital  fascia  passes 
forward  to  blend  with  the  orbital  periosteum  at  the  orbital  margin  and  to  the  deep 
surface  of  the  palpebral  fascia  in  the  eyelids,  thus  forming  a  funnel-shaped  parti- 


324  SURGICAL  ANATOMY. 

tion  which  supports  the  fornix  of  the  conjunctiva.  The  posterior  lamina  turns 
backward  behind  the  posterior  one-tliii'd  of  tlie  eyeball,  and  loosely  envelops  the 
optic  nerve  and  its  sheath. 

The  anterior  lamina  is  a  strong  membrane  throughout  its  extent,  and  that 
portion  of  it  beneath  the  eyeball  has  been  called  the  suspensory  ligament  of  the  eye- 
ball because,  after  excision  of  the  superior  maxilla,  the  lower  portion  of  the 
anterior  lamina  forms  a  hammock-like  sling  which  supports  the  eyeball  and 
prevents  it  from  sinking  downward.  This  ligament  is  attached  externally  to  the 
malar  bone,  and  internally  to  the  crest  of  the  lacrymal  bone.  Where  the  four 
rectus  muscles  are  located  the  anterior  lamina  is  stronger  and  forms  check  ligaments 
— the  external  and  internal  check  ligaments  being  the  stronger.  The  external 
check  ligament  passes  outward  and  forward  from  the  tendon  of  tlie  external  rectus 
muscle  and  under  the  lacrymal  gland  to  be  attached  to  the  malar  Inine  just  behind 
the  external  palpebral  ligament.  The  internal  check  ligament  passes  inward  from 
the  internal  rectus  muscle  to  be  attached  to  the  upper  part  of  the  crest  of  the  lac- 
rymal bone  behind  the  tensor  tarsi  muscle.  The  check  ligaments  of  the  rectus 
muscles  prevent  extreme  action  of  these  muscles,  and  after  the  external  or  internal 
rectus  muscle  is  divided,  prevent  the  belly  of  the  muscle  from  retreating  far  back 
into  the  orbit. 

The  capsule  of  Tenon  is  the  membrane  which  envelops  the  posterior  two- 
thirds  of  the  eyeball.  It  is  a  thin,  translucent,  fibrous  membrane  formed  by  the 
posterior  lamina  and  part  of  the  anterior  lamina  of  the  orbital  fascia,  and  extends 
from  the  insertions  of  the  rectus  muscles  backward  over  the  sclerotic  coat  of  the 
eyel:)all  almost  to  the  place  of  entrance  of  the  optic  nerve.  Here  it  is  reflected 
backward  over  the  sheath  of  the  optic  nerve  to  the  apex  of  the  orljit.  The  capsule 
approaches  the  sheath  of  the  optic  nerve  in  passing  toward  the  apex  of  the  orbit, 
but  does  not  blend  with  it.  The  space  between  the  sheath  of  the  optic  nerve  and 
the  capsule  of  Tenon  is  the  supra-vaginal  lymph-space,  and  that  between  the  sclerotic 
coat  and  the  capsule  is  Tenon's  space.  These  are  both  lymph-spaces  and  are  in 
communication.  Tlie  capsule  of  Tenon  is  attached  to  the  sclerotic  coat  and  the 
sheath  of  tlio  optic  nerve  by  loose  areolar  tissue  wliieh  permits  free  movement  of 
the  eyeball.  The  orbital  surface  of  the  capsule  is  in  relation  with  the  orbital  fat. 
The  capsule  first  comes  into  contact  with  the  rectus  muscles  near  the  equator  of 
the  eyel)all,  where  the  capsule  is  pierced  by  the  tendons  of  these  muscles.  The 
anterior  margin  of  the  capsule  of  Tenon  forms  a  circular  line  connecting  the 
insertion  of  tlio  rectus  muscles. 

The  posterior  two-thirds  of  the  eyeball  and  the  capsule  of  Tenon  might  be 
said  to  form  a  ball-and-.socket  joint,  permitting  the  various  rotatory  and  gliding 
movements  of  the  eyeball.     The  socket  of  the  joint,  or  the  capsule  of  Tenon,  is 


PLATE  LXXVlil. 


Superior  oblique  m 
Superior  oblique  tendon^ 

Internal  rectus  m 
Supratrochlear  n 
Supraorbital  n. 
Superior  rectus  m.    \ 
Levator  palpebrae  superioris  m 
Orbital  fat 
Inferior  oblique  m. 
Lacrymal  gland^        \  \  \ 


Nasal  n 


Optic  n. 


External  rectus  m. 

Lacrymal  n 
Lenticular  ganglion 
Sensory  root  of  ganglion 

Inferior  maxillary  n.' 
Superior  maxillary 

Gasserian  ganglion' 


Long  posterior 
ciliary  n. 

Frontal  n. 
Nasal  n. 
6th  cranial  n. 
3d  cranial  n. 
Ophthalmic  div.Sth  cranial  n. 
anial  n. 

ent  br.of  4th  n. 
al  n. 


Sensory  root 


NERVES  AND  MUSCLES  OF  ORBIT. 
326 


THE   ORBIT.  327 

lu'M  in  position  liy  the  attiirlinients  of  orhikil  fascia,  and  the  globe  is  held  in  the 
socket  chietiy  by  tiie  rectus  muscles. 

After  excision  of  the  eyeball  the  nuiscles  of  the  orbit  are  able  to  move  the 
stump  through  their  attachments  to  the  capsule  of  Tenon. 

The  frontal  nerve. — Of  the  three  branches  of  the  ophthalmic  division  of  the 
tiflli  nerve,  the  lacryuial,  the  nasal,  ami  the  frontal,  the  last  mentioned  is  by  far 
the  largest,  and  can  be  regarded  as  the  continuation  of  the  main  trunk.  It  gains 
entrance  to  the  orbit  by  way  of  the  sphenoid  fissure,  lying  external  and  on  a  plane 
slightly  inferior  to  the  fourth  nerve.  It  then  passes  forward  upon  the  levator 
palpebraj  superioris  muscle,  between  it  and  the  orbital  periosteum.  At  a  point 
about  midway  between  the  sphenoid  fissure  and  the  supra-orbital  notch  it 
divides  into  its  terminal  branches — the  supra-orbital  and  the  supra-trochlear. 

The  supra-orbital  nerve  continues  forward  in  the  line  of  the  frontal  nerve, 
and  with  the  supra-orbital  artery  leaves  the  orbit  by  way  of  the  supra-orbital 
foramen  or  notch.  It  then  tui'us  upward-  on  the  forehead,  and,  dividing  into  an 
internal  and  an  external  branch,  supplies  the  scalp  as  far  back  as  the  lambdoid 
suture.  At  the  su[)ra-orbital  foramen  it  gives  ofi'  a  few  filaments  to  the  upper 
eyelid. 

The  supra-trochlear  nerve  runs  toward  the  inner  side  of  the  orbit,  and,  as  its 
name  implies,  passes  over  the  pulley  of  the  superior  oblique  muscle.  There  it 
gives  off  a  twig  which  communicates  with  the  infra-trochlear  branch  of  the  nasal 
nerve.  It  then  passes  out  of  the  orbit  accompanied  by  the  frontal  artery,  gives  a 
few  twigs  to  the  inner  part  of  the  upper  eyelid,  supplies  the  structures  around  the 
inner  canthus  of  the  eye  and  root  of  the  nose,  and  sends  a  few  filaments  to  the 
lining  membrane  of  the  frontal  sinus. 

The  lacrymal  nerve  is  the  smallest  branch  of  the  ophthalmic  division.  It 
enters  the  orbit  through  the  sphenoid  fissure  external  to  and  slightly  below  the 
frontal  nerve.  It  then  courses  along  the  outer  wall  of  the  orl)it  above  the  upper 
margin  of  the  external  rectus  muscle  accompanied  b}'  the  lacrymal  artery.  .Just 
behind  the  lacrymal  gland  it  forms  a  loop  of  communication  with  the  temporal 
branch  of  the  orbital  or  temporo-malar  nerve.  From  this  loop  and  the  immediate 
portion  of  the  nerve,  twigs  are  given  off  which  enter  the  lacrjnnal  gland.  The 
remainder  of  the  nerve  continues  forward,  pierces  the  palpebral  fascia,  and  supplies 
the  skin  and  conjunctiva  around  the  outer  canthus  of  the  eyelids. 

The  fourth,  pathetic,  or  trochlear  nerve  enters  the  orliit  through  the  inner 
end  of  the  sphenoid  fissure,  occuj)ying  tlic  highest  position  of  all  the  structures 
which  traverse  it,  and  lying  above  and  to  the  inner  side  of  the  frontal  nerve.  It 
is  the  smallest  of  all  the  cranial  nerves.  It  passes  over  the  origin  of  the  levator 
palpebrse  superioris  muscle,  lies  to  the  hiner  side  of  the  frontal  nerve,  and  enters 


328  SURGICAL   A K ATOMY. 

the  orbital  surface  of  the  superior  oblique  muscle,  to  which  alone  it  is  dis- 
tributed. 

The  lacrymal  gland  is  a  distinctly  lobulated  structure,  which  lies  in  the 
outer  part  of  the  orbit  under  the  external  angular  process  of  the  frontal  bone. 
It  is  composed  of  two  portions  of  unecjual  size,  Avhich  are  separated  by  the 
aponeurotic  expansion  of  tlie  levator  palpebrse  superioris  muscle.  The  sepa- 
ration is  not  perfect,  there  being  gaps  which  allow  of  communication  between 
the  portions  of  the  gland.  Of  the  two  portions,  the  upper  is  by  far  the  larger, 
and  is  called  the  superior  or  orbital  jwrtion,  or  superior  lacrymal  gland  ;  the 
lower  and  smaller  part  is  called  the  inferior  or  palpebral  portion,  or  inferior 
lacrymal  gland. 

The  superior  lacrymal  gland,  as  stated,  comprises  the  main  part  of  the  gland. 
It  is  about  the  size  of  a  small  almond.  Its  upper  surface  is  convex,  and  its  lower 
surface  concave.  It  is  inclosed  by  a  capsule,  from  which  run  fibrous  trabeculte  to 
be  inserted  into  the  posterior  border  of  the  orbital  margin.  These  bands  are  called 
the  suspensory  ligaments  of  the  lacrymal  gland. 

The  inferior  lacrymal  gland  is  looser  in  texture.  It  extends  into  the  outer 
one-third  of  the  upper  eyelid,  and  can  be  readily  seen  in  this  position  when  the 
eyelid  is  everted. 

The  lacrymal  gland  secretes  the  tears,  which  flow  through  ten  to  fifteen  ducts 
into  the  outer  part  of  the  superior  conjunctival  fornix  about  four  millimeters 
above  the  upper  margin  of  the  tar.sal  cartilage.  The  tears  flow  thence  inward 
over  the  ocular  conjunctiva  to  the  puncta  lachrymalia,  and  pass  through  the 
lacrymal  canaliculi,  lacrymal  sac,  and  lacrymo-nasal  duct  into  the  inferior  meatus 
of  the  nose. 

The  Muscles  of  the  Orbit  are  the  levator  palpebra3  sujierioris,  superior  oblique, 
superior  rectus,  external  rectus,  internal  rectus,  inferior  rectus,  and  inferior  oblique. 
^\lth  one  exception — the  inferior  oblique — they  arise  from  the  margin  of  the  optic 
foramen  and  diverge  as  they  pass  forwai'd  to  their  insertion. 

The  levator  palpebrae  superioris  muscle  pursues  a  forward  course  between 
the  orbital  periosteum  and  the  superior  rectus  muscle,  which  lies  innnediately 
below  it.  It  arises  from  the  orbital  roof,  above  and  in  front  of  the  optic  foramen, 
and  passes  forward,  gradually'  widening.  It  expands  into  a  broad  aponeurosis, 
passes  between  the  two  portions  of  the  lacrymal  gland,  and  splits  into  three 
lamellaj.  Tlic  up))ermost  lainella  blends  witli  the  supc'rior  orl)ito-tarsal  ligament; 
the  miildlc  lamella,  the  most  easily  demonstrable,  is  inserted  into  the  anterior 
surface  of  tiie  upper  l)order  of  the  tarsal  cartilage  ;  the  lower  lamella  is  attached 
to  the  conjunctival  fornix.  The  margins  of  the  tendon  are  attached  to  the  margin 
of  the  orbit,  and  thus  any  excessive  action  of  the  muscle  is  prevented. 


PLATE  LXXIX, 


Orbital  fat 
Levator  palpebrae  superioris  rn 


Superior  oblique  tendon 
Pulley 


Internal  rectus  m. 


Eyeball 


Lacrymal  gland 

Inferior  oblique  m 
External  rectus 


Optic  n. 


Superior  oblique  m. 
Levator  palpebrae  superioris  m. 
Superior  rectus  m. 


MUSCLES  OF  ORBIT. 
330 


THE   ORBIT.  331 

Action. — It  raises  the  upper  eyeliil  ami  ntains  it  in  that  position.  Tlic  mu.sde 
rehixt's,  an<l  the  eyelid  falls  as  one  becomes  sleepy. 

Nkkvk  Supply." — From  the  superior  division  of  the  motor  oculi  nerve,  a 
branch  which  pierces  the  superior  rectus  muscle. 

The  superior  oblique  muscle  takes  its  origin  from  the  orbital  roof  at  the 
ni>I)er  and  inner  margins  of  the  optic  foramen.  It  extends  as  a  fleshy  belly  along 
the  upi)er  and  inner  part  of  the  orljital  wall  above  the  internal  rectus  muscle. 
It  then  narrows  into  a  shining,  slender  tendon,  which  enters  the  ring-like  pulley 
attached  to  the  frontal  bone.  Leaving  the  pulley,  the  tendon  changes  its  course  to 
an  outward  and  a  backward  direction.  It  then  passes  under  the  superior  rectus 
muscle,  an<l  expamls  to  1)0  inserted  into  the  sclera  midway  between  the  entrance 
of  the  optic  nerve  and  the  margin  of  the  cornea,  and  between  the  suj^erior  rectus 
and  external  rectus  muscles. 

The  pulley  or  trochlea  of  the  superior  oblique  muscle  is  a  fibro-cartilaginous 
ring,  which  is  attached  bj^  a  fibrous  plate  to  the  trochlear  fossa  in  the  under 
surface  of  the  orbital  plate  of  the  frontal  bone.  The  ring  is  lined  by  a  synovial 
sheath,  and  this  sheath  is  continued  over  its  contained  tendon.  Chronic  serous 
effusion  into  this  synovial  sheath  sometimes  exists  in  persons  past  middle  life,  and 
causes  a  cystic  swelling  at  the  upper  and  inner  jiortion  of  the  upper  eyelid. 

Action. — It  rotates  the  eyeball  inward,  and  as  the  muscle  is  inserted  into  the 
posterior  portion  of  the  globe,  it  draws  the  cornea  downward  and  slightly  abducts 
it.  It  counteracts  the  tendency  of  the  inferior  rectus  muscle  to  rotate  the  cornea 
outward,  and  the  tendency  of  the  superior  and  inferior  recti  muscles  to  adduct  the 
cornea. 

Nerve  Supply. — From  the  pathetic  or  fourth  cranial  nerve. 

Di.ssECTioN. — Divide  the  frontal  nerve  and  levator  palpebr^e  superioris  muscle, 
and  di.ssect  the  latter  free  from  the  underlying  structures.  While  dissecting  up  the 
levator  palpebrse  superioris  muscle,  a  nerve  filament  should  be  observed  which 
passes  through  tlie  underlying  muscle — the  superior  rectus — and  enters  the  under 
surface  of  the  posterior  portion  of  the  levator  palpebrse  superioris  muscle.  This  is 
the  branch  of  the  oculo-motor  nerve,  which  supplies  that  muscle. 

The  superior  rectus  muscle  is  now  fully  exposed.  It  arises  from  the  upper 
portion  of  the  anterior  margin  of  the  optic  foramen,  and  becomes  broader  as  it 
passes  forward  between  the  levator  palpebrse  superioris  muscle  and  the  optic  nerve. 
It  is  inserted  by  a  thin,  expanded  tendon  into  the  sclera,  aljout  one-fuvirth  to  one- 
third  of  an  inch  liehind  the  upper  margin  of  the  sclero-corneal  junction. 

Action. — It  rotates  the  eyeball  upward,  in  addition  to  adducting  and  rotating 
the  cornea  inward — i.  e.,  it  carries  the  cornea  upward,  adducts  it,  and  slightly 
rotates  it  inward. 


332  SURGICAL  ANATOMY. 

Neeve  Supply. — From  the  superior  division  of  the  motor  oculi  nerve. 

Dissection. — This  is  a  very  important  stage  of  the  dissection,  and  if  care  is 
not  exercised,  some  of  the  important  structures  will  be  destroyed.  Divide  tlie 
superior  rectus  muscle  and  reflect  it.  While  dissecting  this  muscle  free  from  the 
underlying  structures,  observe  a  nerve  filament  entering  the  under  surface  of  the 
posterior  portion  of  the  divided  muscle.  This  nerve  is  the  superior  division  of  the 
oculo-motor  nerve,  and,  as  previously  stated,  sends  a  perforating  branch  through 
the  superior  rectus  muscle  to  sujjply  the  levator  palpebrae  superioris  muscle. 
Remove  a  quantity  of  loose  fat,  and  when  working  on  the  outer  side  of  the  optic 
nerve,  take  especial  care  not  to  injure  the  lenticular  ganglion  or  its  connections. 
The  optic  nerve,  as  well  as  numerous  structures  above  and  upon  each  side  of  it, 
will  now  be  exposed.  These  are  the  nasal  nerve,  the  ophthalmic  artery  and  vein, 
and  the  long  ciliary  branches  of  the  nasal  nerve,  all  of  which  cross  the  optic 
nerve.  There  may  also  be  found  the  short  ciliary  nerves.  These  are  more 
numerous  than  the  long  ciliary  nerves,  and  one  of  the  largest  should  be  selected 
and  followed  backward  until  its  source  of  origin,  the  lenticular  ganglion,  is 
reached.  By  careful  work  the  roots  of  this  ganglion  can  be  worked  out  bj'  tracing 
them  backward  from  the  ganglion.  They  will  lead  to  the  nasal  nerve,  the  inferior 
division  of  the  oculo-motor  nerve,  and  the  cavernous  jilexus  of  the  sympathetic 
nerve. 

In  the  posterior  portion  of  the  orbit  the  third  nerve,  the  nasal  branch  of  the 
ophthalmic  nerve,  the  sixth  nerve,  and  the  oj^hthalmic  vein  can  be  seen  passing 
between  the  heads  of  the  external  rectus  muscle. 

In  the  anterior  portion  of  the  orbit  the  reflected  tendon  of  the  superior  oblique 
muscle  can  now  be  more  readily  seen,  for  reflection  of  the  superior  rectus  muscle 
has  exposed  its  terminal  portion. 

The  Nasal  Nerve  is  a  branch  of  the  ophthalmic  division  of  the  fifth  nerve. 
It  gains  access  to  the  orbit  through  the  sphenoid  fissure,  and  passes  between  the 
two  heads  of  the  external  rectus  muscle  and  between  the  divisions  of  the  oculo- 
motor nerve.  It  then  crosses  to  the  inner  wall  of  the  oi-bit,  passing  over  the  optic 
nerve  and  immediately  under  the  superior  rectus  muscle,  taking  a  position  between 
the  superior  oblique  muscle  and  the  internal  rectus  muscle.  After  giving  oS  the 
infra-trochlear  branch,  it  leaves  the  orbit  through  the  anterior  ethmoid  foramen. 
It  tlicn  takes  tlie,  following  course  :  Having  passed  through  the  anterior  ethmoid 
foramen,  it  again  becomes  an  occupant  of  the  cranial  cavity,  lying  between  the 
dura  mater  and  the  cribriform  plate  of  the  ethmoid  bone.  Here  it  leaves  the 
cranial  cavity  through  the  ethmoid  fissure,  or  nasal  slit  at  the  .side  of  the  crista 
galli,  and  becomes  an  occupant  of  the  nasal  fossa.  It  has  thus  traversed  in 
succession  the  cranial  cavity,  the  orbit,  the  cranial  cavity  again,  and,  finally,  the 


PLATE  LXXX, 


Superior  rectus  m 

Levator  palpebrae 
superioris  m. 


Eyeball 

Muscular  br.  of 
ophthalmic  a 


Lacrymal  gland 
Inferior  oblique  m 


Posterior  ciliary  a. 
Supraorbital  a. 
Superior  ophthalmic  v. 

Tendon  of  superior  oblique  m. 
nternal  rectus  m. 
Ophthalmic  a. 

Pulley  of  superior  oblique  m. 
Anterior  ethmoid  a. 


External  rectus  m 
Lacrymal 

Optic  n 
Inferior  ophthalmic  v 

Superior  rectus  m 
Common  ophthalmic  v 

Levator  palpebrae  superioris  m 


Optic  n. 
nternal  carotid  a. 


Optic  chiasm 
Posterior  ethmoij  a. 
Superior  oblique  m. 


phthalmic  a. 
Ligament  of  Zinn 


ARTERIES  AND  VEINS  OF  ORBIT. 


THE   ORBIT.  335 

niiwil  cavity.  It  tlien  gives  off  an  inlrrunl  and  an  oxtia-nal  Krancli,  ami  continues 
as  the  anterior  or  terminal  branch. 

The  internal  or  septal  branch  supplies  the  anlrrior  ])art  of  the  septinn. 

The  e.rteriKil  hndivli  supjilies  llir  anterior  portion  of  the  niiddlc  and  infericjr 
turbinated  bones  and  the  nuieons  niend)rane  oC  the  outer  nasal  wall. 

The  anterior  or  terminal  branch  runs  downward  in  the  groove  on  the  under 
surfiice  of  the  nasal  bone,  passes  between  the  lower  edge  of  the  nasal  bone  and  the 
superior  lateral  nasal  cartilage,  and  supplies  the  sides  and  tijj  of  the  nose. 

The  branches  of  the  nasal  nerve  in  the  orbit  are  four  in  luunber :  the  long 
root  to  the  lenticular  ganglion,  the  two  long  ciliary  nerves,  and  the  infra-trochlear 
nerve. 

The  branch  to  the  lenticular  ganglion,  known  as  the  long,  upper,  or  sensory  root 
of  that  ganglion,  arises  from  the  nasal  nerve  as  it  passes  between  the  two  heads  of 
the  external  rectus  muscle.  It  is  very  slender,  and  measures  about  one-half  of  an 
inch  in  length.  It  passes  along  the  outer  side  of  the  optic  nerve,  and  enters  the 
posterior  superior  angle  of  the  lenticular  ganglion. 

The  long  ciliary  nerves  are  usually  two  in  number.  They  arise  from  the  nasal 
nerve  as  it  crosses  the  optic  nerve,  and  run  along  the  inner  side  of  the  optic 
nerve  to  enter  the  eyeball  by  piercing  the  sclera.  One  of  these  nerves  usually 
unites  with  one  of  the  short  ciliary  irerves.  Their  course  between  the  sclera  and 
choroid  is  described  with  the  eyeball. 

The  infra-trochlear  nerve  arises  from  the  nasal  nerve  just  before  that  nerve 
enters  the  anterior  ethmoid  foramen.  It  traverses  the  inner  orbital  wall  below 
the  superior  oblique  muscle  and  its  pullej'.  It  forms  a  loop  of  communication 
with  the  supra-trochlear  nerve  at  times  behind,  but  usually  in  front  of,  the  pulley 
of  the  superior  oblique  muscle.  It  supplies  the  region  around  the  inner  canthus 
of  the  eyelids,  including  the  lacrymal  sac  and  the  lacrymal  caruncle. 

The  Ophthalmic  Artery  is  a  liranch  of  the  cavernous  portion  of  the  internal 
carotid  artery.  It  enters  tlie  orl)it  by  passing  through  the  optic  foramen  in 
company  with  the  optic  nerve,  holding  a  position  to  the  outer  side  of,  and  a  little 
below,  the  nerve.  The  ophthalmic  artery,  like  arteries  in  other  parts  of  the  body 
in  which  the  tissues  must  be  freely  movable, — e.  g.,  the  facial  and  splenic  arteries, 
— is  very  tortuous,  to  allow  of  its  elongation.  At  first  it  lies  to  the  outer  side 
of  the  optic  nerve,  soon  crossing  over  that  nerve  and  running  along  and  near  the 
internal  orbital  wall,  between  the  superior  rectus  and  the  internal  rectus  muscle. 
At  the  inner  canthus  of  the  eyelids  it  terminates  by  dividing  into  the  nasal  and 
frontal  arteries. 

The  branches  of  the  ophthalmic  artery  are  the  lacrymal,  ethmoid,  supra- 
orbital, retinal,  ciliary,  muscular,  i)alpeljral,  nasal,  and  frontal. 


336  SURGICAL   ANATOMY. 

The  lacrymal  artery  is  given  off  from  the  oplithahnic  artery,  between  the 
superior  rectus  and  the  external  i-ectus  muscle,  soon  after  the  ophthalmic  artery  has 
entered  the  orbit.  It  accomj^anies  the  lacrymal  nerve  to  the  lacrymal  gland, 
which  it  supplies,  finally  terminating  in  the  conjunctiva  and  eyelids.  It  sends  off 
twigs  as  follows  :  (1)  A  recurrent  branch,  which  passes  backward  through  the 
sphenoid  fissure  to  anastomose  with  the  middle  meningeal  artery  ;  (2)  muscular 
branches  to  the  external  rectus  muscle  ;  (3)  malar  branches,  which  traverse  the 
malar  bone  to  enter  the  temporal  fossa,  one  anastomosing  with  the  deep  temporal 
arteries  and  middle  temporal  artery,  and  the  other  with  the  transverse  facial 
artery ;  (4)  palpebral  branches,  which  form  an  arch  in  each  eyelid  with  the 
palpebral  branches  of  the  ophthalmic  artery ;  and  (5)  some  anterior  ciliary 
branches. 

The  supra-orbital  artery  arises  from  the  ophthalmic  artery  as  that  vessel 
crosses  the  optic  nerve.  It  accompanies  the  frontal  nerve  upon  the  levator 
palpebrte  superioris  muscle,  emerging  upon  the  forehead  through  the  supra-orbital 
foramen.  Having  reached  the  forehead,  it  divides  into  a  superficial  and  a  deep 
branch,  the  former  ramifying  in  the  superficial  fascia,  and  the  latter  in  the  areolar 
tissue  layer  of  the  scalp.  It  anastomoses  with  the  anterior  temporal  arterj',  the 
angular  artery,  and  the  supra-orbital  artery  of  the  opposite  side.  Its  branches  are  : 
(1)  Periosteal,  to  the  roof  of  the  orbit ;  (2)  muscular,  to  the  adjacent  muscles ;  (3) 
diploic,  to  the  diploe  and  frontal  sinus  ;  (4)  trochlear,  to  the  pulley  of  the  superior 
oblique  muscle;  and  (5)  palpebral,  to  the  upper  eyelid. 

The  central  artery  of  the  retina  arises  from  the  ophthalmic  artery  just 
anterior  to  the  optic  foramen.  It  enters  the  optic  nerve  obliquely,  about  one-half 
of  an  inch  behind  the  eyeball,  and  traverses  the  nerve  to  reach  the  interior  of  the 
ej^eball  and  supply  the  retina. 

Ciliary  arteries. — Of  these  there  are  three  sets — short  posterior,  long  posterior, 
and  anterior. 

The  short  posterior  ciliary  arteries  are  about  twelve  in  number,  and  arise  from 
the  ophthalmic  arter}'.  They  run  tortuouslj^  forward  and  pierce  the  sclerotic  coat 
in  a  ring  around  the  optic  nerve,  to  be  distrilnited  to  the  choroid  coat  of  the 
eyeball. 

The  lovy  posterior  ciliary  arteries  are  two  in  number,  and,  arising  from  the 
ophthalmic;  artery,  pass  forward  on  each  side  of  the  optic  nerve  to  pierce  the 
sclerotic  coat  of  the  eyeball.  They  then  run  between  the  choroid  and  sclerotic  coats 
as  far  forward  as  the  ciliary  body  and  iris. 

The  anterior  ciliary  arteries  are  branches  of  the  muscular  and  lacrymal  arteries, 
and  are  about  eight  in  number.  They  pass  forward  in  company  with  the  tendons 
of  the  rectus  muscles,  and  run  beneath  the  conjunctiva.     They  then  pierce  the 


THE   ORBIT.  337 

sclera,  about  one-fourtli  of  an  inch  behind  the  sclero-corneal  junction,  and  termi- 
nate in  the  great  arterial  circle  around  the  iris  and  in  the  ciliary  processes. 

The  ethmoid  arteries  are  two  in  number — posterior  and  anterior. 

'^he  posterior  etliDioiil  artcnj  passes  outward  between  the  internal  rectus  muscle 
and  the  superior  oblique  muscle,  and  enters  the  posterior  ethmoid  foramen. 
Having  reached  the  posterior  ethmoid  cells,  it  gives  off  branches  which  nourish 
their  walls  and  the  lining  mucous  membrane.  It  then  enters  the  cranial  cavity, 
and  gives  off  branches  to  a  small  area  of  dura  mater  and  nasal  branches  Mdiich 
pass  downward  through  the  cribriform  plate  of  the  ethmoid  bone,  to  supj^ly  the 
mucous  membi'ane  of  the  roof  of  the  nose. 

The  anterior  ethmoid  artery  is  larger  than  the  posterior  ethmoid  artery,  and 
traverses  the  anterior  ethmoid  foramen  in  company  with  the  nasal  nerve.  It 
accompanies  the  nerve  in  the  cranial  cavitj',  and  out  of  that  cavit}'  through  the 
ethmoid  fissure  into  the  nose.  Its  branches  are  the  following  :  (1)  Ethmoid,  to  the 
walls  and  mucous  membrane  of  the  anterior  ethmoid  cells;  (2)  meningeal,  to  the 
dura  mater  in  the  anterior  cranial  fossa ;  (3)  naml,  to  the  outer  and  anterior  part 
of  the  mucous  membrane  of  the  nose ;  (4)  frontal,  to  the  frontal  sinus ;  and  (o) 
terminal,  which  accompanies  the  terminal  branch  of  the  nasal  nerve  to  the  skin  of 
the  nose. 

The  muscular  branches  of  the  ophthalmic  artery  are  variable  in  number 
and  origin,  and  are  distributed  to  the  muscles  of  the  orbit.  They  give  off  the 
greatest  number  of  the  anterior  ciliarj'  arteries. 

The  palpebral  arteries  are  two  in  numljer — superior  and  inferior.  They  arise 
from  the  o])hthalmic  arter}^,  either  separately  or  by  a  common  trunk,  almost 
opposite  the  pulley  of  the  superior  oblique  muscle.  They  pass  one  above  and  the 
other  below  the  tendo  oculi,  run  between  the  tarsal  cartilage  and  the  orbicularis 
palpebrarum  muscle,  near  the  edge  of  the  eyelid,  and  anastomose  with  the  palpebral 
branches  of  the  lacrymal  artery,  thus  forming  a  vascular  arch  in  each  eyelid. 
They  also  supply  the  lacrymal  duct  and  caruncle  and  the  adjacent  conjunctiva. 

The  nasal  artery  is  the  lower  terminal  branch  of  the  ophthalmic  artery.  It 
leaves  the  orbit  by  piercing  the  orbito-tarsal  ligament  or  palpebral  fascia  above  the 
tendo  oculi.  It  then  passes  down  the  side  of  the  nose,  and  anastomoses  with  the 
angular  or  lateral  nasal  branches  of  the  fiicial  artery. 

The  frontal  artery  is  the  upper  of  the  terminal  branches  of  the  ophthalmic 
artery.  It  leaves  the  orbit  at  the  inner  canthus  of  the  eyelids  by  piercing  the 
palpebral  fascia,  and  passes  upward  on  the  forehead,  anastomosing  with  the  supra- 
orbital artery,  the  anterior  temporal  artery,  and  the  frontal  artery  of  the  opposite  side. 

The  Ophthalmic  Veins  are  three  in  number.  They  are  the  common  oph- 
thalmic vein,  superior  ophthalmic  vein,  and  inferior  ophthalmic  vein.     Neither 

.S—        11—22 


338  SURGICAL  ANATOMY. 

these  veins  nor  their  tributaries  have  valves.  Their  anastomosis  is  fairly  free,  the 
communications  being  with  veins  corresponding  to  the  arteries  with  which  the 
branches  of  the  ophthalmic  artery  anastomose. 

The  common  ophthalmic  vein,  fornied  l>y  the  union  of  the  superior  and 
Infei'ior  ophthalmic  veins,  is  short  and  thick.  It  passes  between  the  heads  of  the 
external  rectus  muscle,  through  the  sphenoid  fissure,  and  enters  the  cavernous 
sinus. 

The  superior  ophthalmic  vein  is  considerably  larger  than  the  inferior  oph- 
thalmic vein.  It  commences  at  the  inner  portion  of  the  upper  eyelid  by  a  free 
anastomosis  with  the  frontal,  supra-orbital,  and  angular  A-eins,  and,  following  a 
straighter  course  than  the  ophthalmic  artery,  crosses  over  the  optic  nerve  to  reach 
the  inner  end  of  the  sphenoid  fissure,  where  it  joins  the  inferior  ophthalmic  vein 
to  form  the  common  ophthalmic  vein. 

The  inferior  ophthalmic  vein  is  formed  by  the  union  of  the  inferior  muscular 
and  posterior  ciliary  veins  in  the  lower  external  portion  of  the  orbit.  It  lies 
below  the  plane  of  the  optic  nerve,  and  communicates  with  the  pterygoid  plexus 
of  veins  by  a  twig  which  passes  throngli  the  spheno-maxillary  fissure.  It  then 
runs  backward  to  the  rear  of  the  orbit,  and  joins  the  superior  ophthalmic  vein, 
as  previously  described.  The  inferior  ophthalmic  vein,  as  well  as  the  sui^erior, 
empties  at  times  directly  into  the  cavernous  sinus. 

Phlebitis  of  the  ophthalmic  veins  may  extend  to  the  cavernous  sinus  and  cause 
fatal  thrombosis. 

Pulsation  of  the  ophthalmic  vein  and  of  the  orbit  may  be  produced  by  an 
arterio-venous  aneurysm  between  the  internal  carotid  artery  and  the  cavernous 
sinus.  Pulsation  of  the  orbit  may  also  be  caused  by  traumatic  aneurysm  of  one  of 
the  arteries  of  the  orbit,  or  pulsation  transmitted  to  the  tenninal  portion  of  the 
ophthalmic  vein  from  an  aneurysm  of  the  internal  carotid  artery. 

The  Lenticular,  Ophthalmic,  or  Ciliary  Ganglion  is  a  small,  reddish  body, 
slightly  larger  than  the  head  of  an  ordinary  pin.  It  is  of  quadrilateral  outline, 
and  both  its  surfaces  are  slightly  convex.  It  lies  about  one-fourth  of  an  inch  in 
front  of  the  sphenoid  fissure,  and  between  the  optic  nerve  on  the  inner  side  and 
the  external  rectus  muscle  on  the  outer  side.  It  is  usually  situated  at  the  outer 
side  of  the  ophthalmic  artery,  to  which  it  is,  at  times,  closely  adherent.  Like  all 
the  sporadic  ganglia  connected  witli  the  fifth  nerve,  it  has  afferent  and  efferent 
filaments.  The  afferent  filaments  are  three  in  number,  and  are  termed  its  roots ; 
the  efferent  filaments  are  the  branches  of  distribution. 

The  roots  are  motor,  .sensory,  and  .?ym]iathetic.  Tlie  motor,  or  short  root,  is 
derived  from  tliat  braneli  of  |1r>  oculn-motor  Ufrvc  whirh  runs  to  the  inferior 
oblique    nuiscle.     It    enters   the  posteriur    iufeiior  angle  of  the   ganglion.     The 


PLATE  LXXXi. 


Frontal  sinu 

Ofifice  of  infundlbulu 

Pulley  of  superior  oblique 
Tendgn  of  superior  oblique  m.- 

Lachrymal  gland 


Tarsal  cartilage  of  upper  eyelid 
Loop  between  orbital 
and  lachrymal  nerves  — 


Inferior  oblique  m 

Bristle  in  orifice  of  antrum 
Antrum  of  Hlghmore 


.Supraorbital  n. 
Supratrochlear  n. 

Levator  palpebrae  m. 
Lachrymal  n. 
Superior  rectus  m. 
Frontal  n. 

Internal  rectus  m. 
Optic  n. 

Short  ciliary  nerves 
,Nasal  n. 

Lenticular  ganglion 
External  rectus  m. 
Inferior  rectus  m. 
Lachrymal  n. 

Jhird  n. 


Sixth  n. 


Ophthalmic  division 
of  fifth  n. 

Gasserian  ganglion 


Trifacial  or  fifth  n. 


ferior  maxillary  n. 


maxillary  n. 


^^^'*>4l!4.i>t§:^^-*>^" 


NERVES  OF  ORBIT. 
339 


THE   OnniT.  341 

sensory  or  long  root  springs  from  {\w  nasal  In-ancli  of  the  ophthalmic  division  of 
the  fifth  nerve.  It  passes  along  the  outer  side  of  the  o[)tic  nerve,  and  enters  the 
IKisterior  superior  angle  of  the  ganglion.  The  sympathetic  root  has  its  origin  in 
the  cavernous  plexus,  and  is  somewhat  difficult  to  dissect  satisfactorily.  It  enters 
the  hack  jiortion  of  the  ganglion  in  one  of  three  ways:  most  commonly  in  com- 
pany with  the  sensory  root,  more  rarely  alone,  in  the  form  of  a  Ininch  of  fhie 
tilanients,  and  least  frequently  in  company  with  the  motor  root. 

Branches. — From  the  anterior  horder  of  the  ganglion  ahout  six  delicate 
filaments  are  given  off,  whicli  run  forward  to  the  eyehall  and,  by  subdividing, 
number  twenty  when  they  reach  the  globe.  The}'  are  termed  the  short  ciliary 
nerves.  They  surround  the  optic  nerve  and  pierce  the  sclerotic  coat  in  a  circle 
aroun<l  the  entrance  of  that  nerve.  Having  penetrated  tlie  sclerotic  coat,  they  are 
joined  by  the  long  ciliary  nerves.  They  are  ordinary  sensory  and  trophic  nerves 
to  the  eyeball,  and  niotor  nerves  to  the  radiating  fibers  of  the  iris,  the  ciliary 
musde,  and  the  sphincter  iridis.  The  motor  oculi  filaments  .supply  the  circular 
muscular  fibers  of  the  iris ;  and  the  symj^athetic  fibers  supply  the  radiating 
muscular  fibers  of  the  iris. 

The  Third,  Motor  Oculi,  or  Oculo-motor  Nerve  lies  in  tlie  outer  wall  of  the 
cavernous  sinus,  holding  the  highest  position  of  all  the  nerves  situated  there.  It 
passes  to  the  sphenoid  fissure,  and  here  divides  into  a  superior  and  an  inferior 
division.  These  divisions  then  pass  through  the  sjjhenoid  fissure  and  between  the 
heads  of  the  external  rectus  muscle,  separated  from  each  other  by  the  nasal  branch 
of  the  ophthalmic  nerve. 

The  superior  division,  the  smaller  of  the  two,  has  already  been  traced.  ■  It 
supplies  the  superior  rectus  muscle  and  the  levator  palpebrse  superioris  muscle. 

The  inferior  division  very  soon  breaks  up  into  three  branches.  Two  of  these 
are  comparatively  short,  and  enter  the  ocular  surface  of  the  two  muscles  to  which 
they  are  distributed, — the  inferior  and  internal  recti  muscles, — the  branch  to  the 
internal  rectus  muscle  passing  under  the  optic  nerve.  The  third  l)ranch  pursues  a 
longer  course,  and  runs  along  the  floor  of  tlie  orbit  to  supply  the  inferior  oblique 
muscle.  It  occupies  the  interval  between  the  inferior  and  external  rectus  muscles 
and  enters  the  inferior  oblique  muscle  at  its  posterior  l)order.  It  gives  off,  near 
its  origin,  the  motor  root  to  the  lenticular  ganglion. 

The  oculo-motor  nerve  supplies  the  lenticular  ganglion  and  the  muscles  of 
the  orbit,  with  the  exception  of  the  external  rectus  and  su[)crior  ob]i(|ue  nniscles. 
Tln-ough  the  lenticular  ganglion  it  .supplies  the  ciliary  nniscle  and  the  .sphinoter  djd»Acrr 
iridis. 

The  Sixth,  or  Abducent  Nerve,  passes  forward  in  the  imier  wall  of  the 
cavernous  sinus,  lying  on  the  outer  side  of,  and  slightly  posterior  to,  the  internal 
carotid  artery.     It  enters  the  orbit  through  the  inner  part  of  the  sphenoid  fissure, 


342  SURGICAL  ANATOMY. 

between  the  inferior  division  of  the  oculo-motor  nerve  and  the  ophthalmic  vein. 
It  then  passes  between  the  heads  of  the  external  rectus  muscle,  to  terminate  in 
the  ocular  surface  of  that  muscle  and  supply  it. 

Arrangement  of  the  Nerves  of  the  Orbit,  in  the  walls  of  the  cavernous  sinus 
and  in  the  sphenoid  fissure,  is  as  follows  :  In  the  outer  ivall  of  the.  cavernous  sinus 
there  are,  from  aliove  downward,  tlie  third  nerve,  the  fourth  nerve,  and  the  ophthal- 
mic division  of  the  fifth  nerve  ;  in  the  inner  wall  is  the  sixth  nerve,  in  relation 
with  the  outer  side  of  the  internal  carotid  artery.  These  nerves  are  separated 
from  the  cavity  of  the  sinus  by  its  endothelial  lining.  In  the  sphenoid  fissure  the 
lacrjanal,  frontal,  and  pathetic  or  fourth  nerve  occupy  a  higher  plane  than  the 
other  nerves,  and  are  found  in  the  order  named  from  without  inward.  They  pass 
above  tlie  origin  of  the  mu.scles,  wliile  the  otlier  nerves  and  the  ophthalmic  vein 
are  lower  down  and  enter  the  orbit  between  the  two  heads  of  the  external  rectus 
muscle.  The  nerves  lying  on  a  lower  plane  in  the  sphenoid  fissure  are,  from  with- 
out inward,  the  superior  division  of  the  oculo-motor  nerve,  the  nasal  nerve,  the 
inferior  division  of  the  oculo-motor  nerve,  and  the  abducent  or  sixth  nerve.  The 
ophthalmic  vein  lies  to  the  inner  side  of  the  sixth  nerve. 

The  optic  nerve  enters  the  orlnt  through  the  optic  foramen,  in  company  witli 
the  ophthalmic  artery,  and  passes  into  the  eyeball  al>out  one-tenth  of  an  inch,  or  2.5 
millimeters,  internal  to  the  posterior  pole  of  that  organ.  It  is  invested  by  a  sheath 
of  dura  mater  and  arachnoid,  and  is  surrounded  by  an  extension  of  the  capsule  of 
Tenon,  the  orbital  fat  and  vessels,  and  the  rectus  muscles.  It  is  pierced  and 
traversed  l)v  the  vena  centralis  retinte  and  arteria  centralis  retina;. 

The  External  Rectus  Muscle  is  seen  along  the  outer  wall  of  the  orbit.  It 
has  two  heads  of  origin  :  tlie  upper  head  arises  from  the  outer  margin  of  the 
optic  foramen,  beneath  the  superior  rectus  muscle,  and  the  lower  head,  partly  from 
the  ligament  or  tendon  of  Zinn  and  partly  from  a  small  spine  of  bone  situated  on 
the  lower  margin  of  the  sphenoid  fissure.  Between  these  two  heads  pass  the  third 
nerve,  the  nasal  nerve,  the  sixth  nerve,  and  the  ophthalmic  vein.  The  external 
rectus  muscle  is  inserted  by  an  expanded  tendon  into  the  sclerotic  coat  of  the  eye- 
ball about  one-fourtli  to  one-tliird  of  an  inch  behind  tlio  outm-  margin  of  tlie  cornea. 

Action. — It  abducts  the  cornea. 

Nerve  Supply. — From  the  abducent  or  sixth  cranial  nerve. 

The  Internal  Rectus  Muscle  lies  along  the  inner  wall  of  the  orbit,  below 
the  superior  iilili(|ni'  umsclc,  oi)litlialiiiic  artery,  ami  nas:il  nerve.  It  arises 
tliniugh  (he  ligament  or  tendon  of  Zinn  from  the  inner  margin  of  the  optic 
foramen,  and  is  inserted  into  tlie  sclerotic  eoat  of  the  eyeball  about  one-fourth  to 
one-third  of  an  inch  lu'liiiid  the  inner  margin  of  the  cornea. 

.V<'ri(:)N. —  It  abducts  the  cornea. 

Xkkve  Supply. — From  the  inferior  division  of  the  third  cranial  nerve. 


PLATE  LXXXII 


Pituitary  body. 


\..avernous  sinus. 


3rd  cranial  n. 


cranial  n. 
Internal  carotid  a. 
.Ophthalmic  n, 


SECTION  OF  CAVERNOUS  SINUS. 


Superior  division  of 
era 


Inferior  division  of 


'•      »  '.liUvv.-'-  ■■■ 


Lacrymal  n. 
Frontal  n. 


4th  cranial  n. 


Ophthalmic  v. 


STRUCTURES  TRAVERSING  SPHENOID  FISSURE. 
34;^, 


PLATE  LXXXIIL 


Superior  rectus  m 


Tendon  of  superior  oblique  m 


Pulley 


Corrugatorsupercilii  m. 

Puncta  lachrymalia 
Meibomian  gland 


Conjunctiva 


Orbital  fat 

Inferior  rectus  m 

Inferior  oblique  m 


Tensor  tarsi  m. 


TENSOR  TARSI  AND  CORRUGATOR  SUPERCILII   MUSCLES. 
346 


TIIK    UlilUT.  347 


Tlic  Inferior  Rectus  Muscle  mises  from  tin-  lower  margin  of  tlic  optic 
fiiraiiu'U  tlu-uUi;li  tlu'  iii;aiiH'iil  cir  trudon  of  Zimi.  It  passes  forward  along  the 
lloor  of  the  orhit  and  licluw  the  dptic  nerve,  and  is  insei'tcd  into  the  sclei'otic 
coat  of  the  eyehall  alniut  iine-t'onrtli  to  one-third  of  an  inch  from  the  lower 
margin  of  tlu'  cornea. 

Action. —  It  depresses  the  cornea,  adducts  it,  and  rotates  it  ontward. 

Nerve  Srrri.v. — From  the  inferior  division  of  the  motor  oculi  or  third 
cranial  nerve. 

The  inferior  rectus  muscle  can  he  hetter  studied  after  the  dissection  of  the 
vessels,  the  nerves,  and  the  other  nmscles  has  been  completed,  and  those  structures 
have  been  removed. 

Ligament  of  Zinn. — By  observation  of  the  ocular  surfaces  of  the  origin  of 
the  J'lxir  rectus  riuisclcs,  it  will  be  seen  that  these  muscles  arise  from  a  common 
tendinous  ring  which  is  attached  around  tire  optic  foramen.  This  common  tendon 
may  be  divided  into  a  superior  and  an  inferior  common  tendon.  The  stqicrior 
common  teniJoti-  is  attached  to  the  upper  mai'gin  and  tlio  upjier  outer  part  of  the 
margin  of  the  optic  ioramen,  and  gives  origin  to  the  superior  rectus  nmscle, 
part  of  the  internal  rectus  muscle,  and  the  upper  head  of  the  external  rectus 
muscle. 

The  inferior  connnon  tendon,  or  ligament  of  Zinn,  is  attached  to  the  lower  pai't 
of  the  inner  margin,  the  lower  margin  and  the  lower  part  of  the  outer  margin  of 
the  optic  foramen,  and  gives  origin  to  the  inferior  rectus  muscle  and  part  of  the 
internal  rectus  muscle,  and  the  lower  head  of  the  external  rectus  nmscle. 

Dissection. — The  inferior  oblique  muscle  is  next  exposed.  Its  position  and 
relations  differ  nnich  from  those  of  the  other  orbital  muscles,  and  it  can  best  be 
seen  after  the  following  dissection  :  Release  the  eyeball  from  any  position  in  which 
it  may  be  held.  Evert  the  lower  eyelid,  and  I'emove  the  conjunctiva  from  it  at  the 
inferior  forni.x.  Remove  the  fat  lying  in  the  floor  of  the  anterior  portion  of,  the 
orbit,  and  clean  the  expo-sed  muscle.  In  doing  this  be  careful  not  to  cut  the  nerve 
which  enters  the  posterior  border  of  the  inferior  oblique  muscle. 

The  Inferior  Oblique  Muscle  arises  by  a  fiat  tendon  from  the  orbital  plate  of 
the  superior  maxilla  to  the  outer  side  of  the  orbital  orifice  of  the  lacrymal  duct. 
It  passes  outward  and  Ijackward  under  the  inferior  rectus  muscle,  and  then  upward 
between  the  globe  and  the  external  i-ectus  muscle.  It  ends  in  a  membranous 
temlon  which  is  inserted  into  the  sclera  on  the  uppiT  and  ()uti_r  side  of  the  globe, 
beloAV  and  external  to  the  insertion  of  the  superior  oblique  nuiscle. 

Action. — It  rotates  the  eyeball  outward,  and  elevates  and  abducts  the  cornea. 
In  abducting  the  cornea  it  counteracts  the  tendency  of  the  su])erior  rectus  muscle 
anil  inferior  rectus  muscle  to  ai.lduct  the  cornea. 


348  SURGICAL  ANATOMY. 

Nerve  Supply. — From  the  longest  brancli  of  the  inferior  division  of  the 
oculo-motor  nerve,  which  enters  the  muscle  at  its  posterior  margin. 

Dissection. — The  ocular  conjunctiva  should  now  be  removed  from  the  scler- 
otic coat  of  the  eyeball  as  far  forward  as  the  margin  of  the  cornea,  so  that  the 
positions  of  the  attachments  of  the  four  rectus  muscles  can  be  observed. 

The  rectus  muscles  are  inserted  by  thin,  flat,  slightly  expanded  tendons  into 
the  sclerotic  coat  of  the  eyeball,  one-fourth  to  one-third  of  an  inch  from  the  margin 
of  the  cornea. 

Action. — The  actions  of  the  rectus  and  oblicjue  muscles  of  the  orbit  are  some- 
what complex,  as  almost  every  movement  of  the  eyeball  is  performed  by  two  or 
more  muscles.  In  considering  the  movements  of  the  eyeball  it  must  be  remem- 
bered that  the  globe  can  not  be  moved  away  from  its  position,  in  which  it  is 
closely  retained  by  the  cajjsule  of  Tenon  and  the  attachments  of  the  orbital  fascia, 
forward  movement  being  prevented  by  the  rectus  muscles.  The  only  movements 
of  the  eyeball  are  rotation  around  any  axis  of  the  globe,  limited  by  the  attach- 
ments of  the  orbital  fascia  existing  between  the  muscles  and  the  adjacent  structures, 
as  the  orbital  periosteum  and  the  palpebral  fascia.  These  movements  are  more 
easily  understood  if  only  the  motion  of  the  cornea  is  considered. 

Adduction  of  the  cornea  is  performed  by  the  internal  rectus  muscle,  and 
abduction  of  the  cornea  by  the  external  rectus  muscle  and  the  two  oblicjue 
muscles. 

Elevation  of  the  cornea,  as  in  looking  directly  up\\-ard,  is  performed  by  the 
superior  rectus  muscle,  the  inferior  obli<]ue  muscle  preventing  adduction  of  the 
cornea  and  rotation  of  the  cornea  inward.  Rotation  of  the  cornea  inward  is 
movement  of  the  uppermost  portion  of  the  cornea  inward  and  downward. 

Depression  of  the  cornea  is  performed  by  the  inferior  rectus  muscle,  the 
superior  oblique  muscle  preventing  adduction  of  the  cornea  and  rotation  of  the 
cornea  outward. 

Rotation  of  the  cornea  inward  is  performed  by  the  superior  rectus  muscle  and 
the  superior  oblique  muscle,  and  rotation  of  the  cornea  outward  b}'  the  inferior 
rectus  muscle  and  the  inferior  oblique  muscle.  Rotation  of  the  cornea  is  not  a 
common  movement,  and  it  occurs  when  the  head  is  inclined  to  one  side. 

Movement  of  the  cornea  in  an  oblique  direction  is  performed  chiefly  by  two 
of  the  rectus  muscles,  as  upward  and  outward  by  the  superior  rectus  and  external 
rectus  muscles. 

Excessive  action  of  the  various  muscles  is  prevented  by  the  attachments  of 
the  anterior  lamella  of  the  orbital  fascia. 

Strabismus,  or  deviation  of  the  sagittal  axis  of  one  eyeball  from  its  normal 
position,  occurs  when  one  or  more  muscles  are  excessivelj^  active  or  the  opposing 


PLATE  LXXXIV. 


Tendo  ocul 
Lacryinal  sac 
Lacrymal  canaliculus 


Middle  turbinatis  bone 
nferior  turbinatis  bone 
Middle  meatus  of  nose 
Inferior  rneatus  of  nose 
Lacryino-nasa!  duct 
Antrum  of  Highmore 


LACRYMAL  APPARATUS, 
350 


THE  LACHYMAL  AI'/'ANATUS.  ?.5l 

muscles  are  insufficiently  active.  This  cnnilition  is  more  commonly  caused  by 
defective  refraction  in  the  affected  eye  or  unc(iiuil  refraction  in  the  two  eyes.  The 
first  requisite  is  to  correct  the  defect  in  refraction,  and  as  a  last  resort  the  tendon 
or  tendons  of  the  liy|ieractive  niust'le  or  nnisclcs  may  l)e  divided.  A fter  division 
of  the  tendon,  e.\treuic  retraction  of  the  nuisele  is  prevented  by  tlie  anterior 
lamella  ot'  the  urhital  fasi'ia. 

I)issEcTioN. — The  temporo-malar  nerve  is  the  last  structure  to  be  dissected. 
The  orbital  contents  must  be  removed  completely,  and  the  nerve  will  be  found  in 
a  pad  of  fat  in  the  retiring  angle  between  the  inferior  and  external  orbital  walls. 

The  Temporo-malar  ur  Orbital  Nerve  arises  from  the  superior  maxillaiy 
nerve  in  the  spheno-maxillary  fossa,  and  reaches  the  orbit  by  passing  through  the 
spheno-maxillary  fis.sure.     It  then  divides  into  two  branches — temporal  and  malar. 

The  temporal  branch  forms  a  loop  of  communication  with  the  lacrymal  nerve, 
and  then  runs  beneath  the  orbital  periosteum  to  reach  the  spheno-malar  foramen. 
Having  traversed  this  foramen  and  entered  the  temporal  fossa,  it  pierces  the 
dee])  layer  of  the  temporal  fliscia.  It  runs  upward  between  the  two  layers  of  the 
temporal  tascia  for  a  short  distance,  and  pierces  the  superficial  layer  of  that  fascia. 
It  communicates  with  the  temporal  branch  of  the  facial  nerve,  ami  is  disti'iliuted 
to  the  skin  of  the  anterior  temporal  region. 

The  malar  branch  runs  forward  iii  the  orbital  fat,  and  leaves  tlie  orbit  b}' 
passing  through  the  malar  foramen.  It  communicates  with  the  malar  branch  of 
the  facial  nerve  and  supplies  the  skin  of  the  cheek. 

The  Lymphatics  of  the  Orbit  jiass  thiough  the  spheno-maxillary  fissure  to 
the  internal  maxillary  and  deep  parotiil  lymphatic  glands. 


THE  LACRYMAL  APPARATUS. 


Dissection. — Insert  slender  probes  into  the  puncta  lachrymalia  and  lacrymal 
canaliculi,  and  open  the  latter  as  far  as  the  lacrymal  sac. 

The  Lacrymal  Canaliculi  are  two  narrow  canals,  one  in  each  eyelid,  extend- 
ing from  the  lacrymal  jmnetum  to  the  lai'rymal  sac.  For  a  short  distance  from 
the  lacrymal  punctum  the  course  of  each  canaliculus  is  vertically  away  from  the 
margin  of  the  lid,  then,  turning  abruptly,  it  forms  a  right  angle,  passes  inward, 
and  pierces  the  inner  division  of  the  ten<1o  oculi  to  reach  the  lacrymal  sac.  Before 
entering  the   lacrymal   sac  the  lacrymal    canaliculi  of  the   ujipcr  and  lower  lids 


352  SURGICAL   ANATOMY. 

frequently  join  and  open  into  the  sac  by  a  common  orifice.     In  passing  a  probe 
into  the  lacrymal  canaliculi  their  angular  course  should  be  remembered. 

Dissection. — Next  make  a  vertical  section  through  the  upper  and  the  lower 
ej^elid,  to  demonstrate  their  several  layers  of  tissue. 

The  Eyelids  are  composed  of  skin,  superficial  fascia,  orbicularis  palpebrarum 
muscle,  areolar  tissue,  i:)alpebral  ligaments,  orbito-tarsal  ligaments,  tarsal  carti- 
lages, Meibomian  glands,  conjunctiva,  vessels,  nerves,  and  lymphatic  vessels.  The 
upper  eyelid  also  contains  the  aponeurosis  of  the  levator  palpebrse  superioris 
muscle.  The  most  superficial  layer  is  the  skin  ;  the  second  layer  is  the  superficial 
fascia,  which  contains  no  fat  in  this  location ;  the  third  layer  is  composed  of  deli- 
cate areolar  tissue  ;  in  the  fourth  layer  are  the  tarsal  cartilage,  the  orbito-tarsal 
ligament,  the  palpebral  ligaments,  the  Meibomian  glands,  and  in  the  upjjer  lid  the 
aponeurosis  of  the  levator  palpebrte  superioris  muscle  ;  the  fifth  layer  is  com- 
posed of  conjunctiva  and  subconjunctival  tissue.  The  eyelids  are  described  in 
volume  I,  pages  512-520. 

Dissection. — Open  the  lacrymal  sac,  and,  after  j^assing  a  probe  through  the 
lacrymo-nasal  duct,  saw  away  the  anterior  wall  of  that  duct. 

The  Lacrymal  Sac  is  the  upper,  dilated  end  of  the  lacrymo-nasal  duct,  and 
rests  in  the  lacrymal  groove,  which  is  a  depression  in  the  lower  anterior  portion 
of  the  inner  wall  of  the  orbit.  The  lacrymal  sac  is  invested  by  a  fibrous  capsule, 
which  is  attached  to  the  margins  of  the  lacrymal  groove,  and  is  continuous  with 
the  orbital  periosteum.  It  is  lined  with  mucous  membrane,  which  is  continuous 
with  that  of  the  lacrymal  canaliculi  and  lacrymo-nasal  duct.  Loose  submucous 
tissue  attaches  mucous  membrane  to  the  fibrous  capsule. 

The  Lacrymo-nasal,  Nasal,  or  Lacrymal  Duct  extends  from  the  lacrjmial 
sac  to  the  uppermost  part  of  the  anterior  portion  of  the  inferior  meatus  of  the 
nose.  It  is  directed  downward  and  slightly  backward  and  outward.  Its  walls  are 
formed  by  the  superior  maxillary,  lacrymal,  and  inferior  turbinated  bones,  and  are 
lined  l)y  mucovis  membrane  continuous  with  that  of  the  nose  and  lacrymal  sac, 
the  sac  and  tlie  duct  forming  the  Lacrymal  Canal.  The  nasal  orifice  of  the 
duct  is  guarded  by  a  valvular  flap  of  mucous  membrane. 

Tlic  Course  of  the  Tears  is  from  the  lacrymal  gland  at  the  outer  part  of  the 
ujipcr  fiiruix  of  the  conjunctiva  and  the  accessory  lacrymal  glands  in  the  eyelids, 
inward  over  the  conjunctiva  to  the  lacrymal  puncta,  and  thence  successively 
tlir(iu,i;li  the  Iiici-yiiial  canaliculi,  lacrymal  sac,  lacrymal  duct,  and  inferior  meatus 
of  the  nose.  IF  the  lower  eyelid  is  everted  or  inverted  so  tiiat  the  tears  do  not 
enter  the  lacrymal  punctum,  or  thei'e  is  an  obstruction  in  the  lacrymal  canaliculi 
or  nasal  duct,  or  the  tears  are  secreted  too-  rapidly  for  the  capacity  of  the  puncta, 
as  in  weeping,  the  tears  flow  over  the  cheek. 


PLATE  LXXXV. 


Orbicularis  palpebrarum 


Skin 
Superficial  fascia 

Median'connective  tissue 


Waldeycr's  glands 

■^^   ■-  J^yCorijunctival  papillae 

Conjunctiva 


Orbicularis  palpebrarum 


Sebaceous  gland  of 


Levator  palpebrae   superioris  m. 
Superior  palpebral  m.of  Mu'ller 


I?    Meibomian  glands  in  tarsal  cartilage 


Duct  of  Meibomian  gland 
weat  gland  of  Moll 


II— -23 


SAGITTAL  SECTION  OF  UPPER  EYELID. 
353 


PLATE  LXXXVl. 


Superior  portion  of  lacrymal  gland 

Inferior  portion  of  lacrymal  gland 

Levator  palpebrae  superioris  m 


Frontal  sinus 


Meibomian  glands 
'Conjunctiva 
Orifices  of  ducts  of  meibomian  glands 
Orifices  of  lacrymal  ducts 


Tensor  tarsi  m. 
Lacrymal  sac 


Lacrymal  canaliculi 


MEIBOMIAN  GLANDS  AND  LACRYMAL  APPARATUS. 


Tin:   FATMALL.  357 

THE  EYEBALL. 

The  eyeball  is  a  globular  body,  so  situated  in  the  orbital  fossa  as  to  be  pro- 
tected by  the  orbital  margins  from  injury  by  large  objects.  It  is  freely  movable 
around  its  axes,  in  order  that  objects  may  be  seen  without  appreciable  muscular 
effort. 

Till'  mobility  of  the  eyeball  is  permitted  by  the  relation  existing  between  the 
globe  and  the  capsule  of  Tenon,  which  has  been  described  with  the  orbit. 
The  eyeball  and  capsule  of  Tenon  form  a  ball-and-socket  joint.  Backward, 
lateral,  vertical,  and  oblique  movements  of  the  eyeball  en  masse  are  prevented  by 
the  attachments  of  the  orbital  fascia  to  the  orbital  margins  and  palpebral  fascia, 
and  forward  movement  of  the  organ  is  checked  by  the  rectus  muscles ;  therefore 
the  only  movements  of  the  eyeball  are  those  of  rotation  around  its  axes.  Exces- 
sive rotation  is  prevented  by  the  attachments  of  the  anterior  lamella  of  the  orbital 
fascia  and  its  thickened  portions,  designated  check  ligaments. 

Exophthalmos,  or  protrusion  of  the  eyeball  from  the  orbit,  may  be  caused  l)y 
tumors  or  foreign  bodies  in  the  orbit,  myopia,  and  enlargement  of  the  eyeball  by 
disease.  It  sometimes  exists  slightly  after  tenotomy  of  one  of  the  rectus  muscles, 
and  may  be  a  sign  of  exophthalmic  goiter. 

Sinking  of  the  eyeball  occurs  after  partial  absorption  of  the  orbital  fat  in 
wasting  diseases,  and  is  associated  with  general  emaciation. 

Being  a  gloliular  liody,  the  eyeball  has  an  anterior  pole,  located  at  the  center 
of  the  cornea  ;  and  a  posterior  pole,  at  the  center  of  the  posterior  segment  of  the 
eye,  which  is  the  portion  covered  by  the  sclera.  It  also  has  an  equator,  midway 
between  the  two  poles ;  an  axis,  or  sagittal  diameter,  connecting  the  two  poles ; 
a  vertical  and  a  transverse  diameter  at  the  equator.  It  is  not  quite  spheric, 
because  the  cornea  is  a  segment  of  a  smaller  sphere,  and  projects  forward  like  a 
watch-glass,  increasing  the  .sagittal  diameter  or  axis;  the  transverse  is  slightly 
greater  than  the  vertical  diameter.  The  axis,  or  sagittal  diameter,  measures 
about  24.5  millimeters;  the  transverse  equatorial  diameter,  aliout  23.9  milli- 
meters ;  and  the  vertical  equatorial  diameter,  about  23.5  millimeters.  From  these 
measurements  it  will  be  seen  that  the  eyeball  is  slightly  elongated  from  behind 
forward,  and  compressed  from  above  downward.  The  axes  of  the  two  eyeballs 
are  parallel  with  each  other,  although  the  axes  of  the  two  orbits  are  divergent 
anteriorly. 

Dissection. — By  the  time  the  orbit  has  been  dissected,  the  liunian  eyeball 
will  be  so  far  decomposed  that  it  can  not  be  easily  nor  profitably  dissected. 
Fortunately,  an  adequate  substitute  is  found  in  the  eye  of  a  pig,  a  sheep,  or  a 
bullock.     Of  these,  the  pig's  eye  corresponds  more  nearly  in  size  to  the  human 


358  SURGICAL  ANATOMY. 

eve ;  but  the  bullock's  eye,  <iii  nceouut  of  its  comparative  grossuess,  is  more 
easily  dissected.  At  least  a  half  dozen  bullocks'  eyes  shuuld  lie  jirocured  before 
the  dissection  is  commenced.  The  globe  must  be  thoroughly  cleaned  down  to  the 
sclerotic.  Perhaps  the  best  way  to  accomplish  tliis  is  as  follows :  With  scis.sors 
and  forceps  make  a  circular  incision  through  the  conjunctiva  close  to  and  parallel 
with  the  margin  of  the  cornea.  The  conjunctiva,  cajisule  of  Tenon,  fat,  fascia,  and 
muscles  are  then  gradually  worked  free  from  the  sclera  from  before  backward, 
as  far  as  the  point  of  entrance  of  the  optic  nerve.  When  about  half  v^ay  back, 
the  vente  vorticosse  will  be  seen  emerging ;  and  when  near  the  optic  nerve,  the 
circle  around  it,  formed  by  the  jiosterior  ciliary  arteries  and  ciliary  nerves,  will 
be  noticed. 

The  Conjunctiva  is  a  mucous  membrane  covering  the  anterior  surface  of  the 
eyeball  and  the  posterior  surface  of  the  eyelids.  It  consists  of  a  parietal  layer, 
the  palpebral  portion,  which  lines  the  eyelids,  and  of  a  visceral  layer,  the  ocular 
portion,  which  covers  the  anterior  one-third  of  the  eyeball.  The  visceral  layer 
is  subdivided  into  a  sclerotic  and  a  corneal  port  inn. 

The  palpebral  portion  of  the  conjunctiva  has  been  described  with  the  eyelids 
under  the  Dissection  of  the  Face. 

The  sclerotic  portion  of  the  conjunctiva  is  loosely  adherent,  except  at  the 
margin  of  the  cornea.  It  contains  small  blood-vessels,  which  are  derived  from  the 
palpebral  vessels,  branches  of  the  lacrymal,  infra-orbital,  supra-orbital,  and  frontal 
vessels,  which  will  not  be  perceptible  under  perfectly  normal  ■  conditions.  Con- 
gested conjunctival  vessels  are  distinguished  from  the  anterior  ciliary  vessels  by 
tlie  fact  that  the  former  move  with  the  conjunctiva,  while  the  latter  are  fixed  in 
the  sclerotic  and  remain  stationary.  The  lax  submucous  tissue  which  connects 
the  conjunctiva  with  the  sclera  permits  the  surgeon  to  slide  flaps  of  conjunc- 
tiva. Its  laxity  accounts  for  the  occurrence  of  subconjunctival  hemorrhages  after 
sudden,  severe  muscular  effort,  as  in  paroxysms  of  wdiooping  cough.  The  hemor- 
rhages, if  associated  with  traumatism  about  the  head,  should  be  viewed  with 
su.spicion,  as  they  may  result  from  fracture  of  the  anterior  fossa  of  the  skull  with 
leakage  of  blood  into  the  orbit.  The  blood  does  not  become  dark  in  color,  but 
remains  reil,  because  oxygen  passes  to  it  through  the  conjunctiva. 

The  corneal  portion  of  the  conjunctiva  consists  of  layers  of  epithelial  cells, 
and  fnrnis  the  anterior  layer  of  the  cornea.  It  is  closely  adherent,  perfectly  trans- 
part'ut,  and  gives  the  cornea  its  mirroi'-like  characteristics.  It  contains  no  blood- 
vessels. 

Extensive  destruction  f)f  the  conjunct i\-ii  may  be  jiroduced  by  caustics  acci- 
dentally introduced  between  the  eyelids  and  \\w  eyeball.  This  more  fre(iuently 
occurs  unilcr  the  lower  eyelid,  on  account  of  its  position.     The  lid  may  adhere  to 


PUTE  LXXXVll. 


Cornea 


Vena  vorticosa 


Optic 
Central  artery  and  vein  of  retina' 

Vitreous  channber 


Sclera 
Choroid 
Retina 


MERIDIONAL  SECTION  OF  EYE. 
360 


tO) 


') 


THE  KYKUAI.L.  Sfil 

the  globe,  causing  symblepharon ;  or  cicatricial  contraction  may  produce  inversion 
of  tlic  cvcliil  anil  cyclaslics  (entropion).  Aillicrence  of  the  two  raw  surfaces  may 
lie  ]ircvcntcil  liy  sliiling  a  bridge  of  conjunctiva  from  above  the  cornea,  and  plac- 
ing it  upon  the  raw  surface  lichiw.  Entrojjion  may  also  bo  caused  by  cicatricial 
contraction  in  cln'onic  conjunctivitis.  In  purulent  conjunctivitis  (purulent 
ophthalmia),  which  is  usually  due  to  intcction  of  the  conjunctiva  by  gonorrheal 
pus,  the  great  danger  lies  in  involvement  of  cornea,  which  may  produce 
permanent  blindness. 

Coats  and  Refracting  Media  of  the  Eye. — The  eyeball  ccjntains  three  sujjcr- 
imiioscd  coats,  inclosing  three  refracting  media,  or  so-called  humor.s.  The  coats, 
named  from  without  inward,  are  a  fibrous,  a  vascular,  and  a  nervous  coat. 

The  refracting  media,  enumerated  fmm  Itcfore  backwaixl,  are  the  aqueous 
humor,  the  crystalline  lens,  and  the  vitreous  humor. 

The  Fibrous  Coat  is  composed  of  two  portions — the  sclera  and  the  cornea. 

Dissection. — To  oliserve  all  parts  of  the  .sclerotic  coat  clearly,  it  should  be 
detached  from  the  underlying  tissues  and  removed.  To  do  this  it  should  be 
incised  at  the  ccjuator — /.  c .,  midway  between  the  center  of  the  cornea  (the 
anterior  jiole)  and  the  corresponding  posterior  point  (the  ])osterior  jiole).  A  sharp 
knife  should  be  u.sed  to  make  a  short  cut  just  deep  enough  to  expose  the  black, 
underlying  choroid.  A  pair  of  sci.ssors  Avith  delicate  blades  and  sharp  points 
should  then  be  used  to  complete  the  equatorial  incision.  Witli  the  handle  of 
the  scalpel  the  halves  of  the  sclerotic  coat  should  l)e  separated  from  the  subjacent 
tissues,  as  one  removes  the  skin  of  an  orange.  At  only  two  points  will  any  dith- 
culty  be  met.  One  is  at  the  entrance  of  the  optic  nerve,  where  it  is  necessary  to 
cut  off  the  optic  nerve  close  to  the  choroid  ;  the  other  point  is  anteriorly,  where 
the  ciliary  body  is  attached  to  the  sclera.  By  the  use  of  slight  force  this  attach- 
ment can  be  torn  with  the  forceps,  and  the  anterior  moiety,  composed  of  the 
sclera  and  the  cornea,  removed  entire.  This  results  in  escape  of  the  acjueous 
humor.  The  remainder  of  the  globe  should  be  laid  aside  in  diluted  alcohol 
until   rcijuircd  for  further  study. 

The  sclera,  or  sclerotic  coat,  incloses  the  posterior  five-sixths  of  the  eyeball, 
the  remaining  anterior  one-sixth  of  its  wall  being  completed  by  the  cornea.  It  is 
incomplete  posteriorly  at  the  entrance  of  the  optic  neiTe,  the  opening  [foramen 
sclent')  being  partially  filled  l>y  a  layer  of  sclerotic  ti.ssue,  called  the  lamina 
crihrom.  It  is  white,  opaque,  and  tough,  and  maintains  the  normal  conformation 
of  the  glolje.  It  consists  of  interlacing  bundles  of  white,  fiT)rous  connective  tissue. 
It  is  thickest  posteriorly,  and  thinnest  just  behind  the  insertions  of  the  rectus 
muscles,  about  one-fourth  to  (jne-third  of  an  inch  or  six  to  eight  millimeters 
from  the  cornea,  where  it  is  sometimes  ruptured  in  cases  of  injury  to  the  eyeball. 


362  SURGICAL  AXATOMY. 

Between  the  cornea  and  the  insertions  of  the  tendons  of  the  rectus  muscles  it 
again  becomes  thicker,  on  account  of  its  reinforcement  by  hbers  from  those  tendons. 
In  disease  of  the  eye,  such  as  gUiueoma,  in  which  there  is  increased  intra-ocular 
tension,  compression  of  tlie  ciliary  nerves  against  the  unyielding  sclerotic  coat 
causes  intense  pain. 

At  its  anterior  margin  the  sclerotic  coat  is  directly  continuous  with  the  cornea, 
and  the  slight  groove  at  this  point  is  called  the  scleral  sulcus.  About  one-fourth  of 
an  inch,  or  six  millimeters,  behind  the  sclero-corneal  junction  the  sclerotic  coat 
receives  the  insertions  of  the  rectus  muscles.  At  this  point  also  it  receives  and 
transmits  the  anterior  ciliary  vessels,  which  form  a, ring  around  the  cornea;  con- 
gestion of  these  vessels  is  evident  in  iritis.  In  the  sclera,  just  Ix-hind  the  sclero- 
corneal  junction,  is  a  circular  l)lood  channel  surrdundiiig  tlie  margin  of  the  cornea  ; 
it  is  called  the  canal  of  Sclilemm.  This  canal  transmits  venous  blood,  and  is  in 
close  relation  with  certain  lymph  spaces  in  the  pectinate  ligament  of  the  iris,  called 
the  spaces  of  Fontana.  In  conjunction  with  the  spaces  of  Fontana  the  canal  of 
Schlemm,  by  absorbing  the  excess  of  aqueous  humor,  is  .supposed  to  maintain  the 
normal  intra-ocular  tension,  exaggeration  of  which  results  in  the  grave  disease, 
glaucoma. 

The  lamina  cribrosa  is  in  the  posterior  portion  of  the  sclera,  and  is  the  place 
of  entrance  of  the  ojitic  nerve,  whose  dural  and  pial  investments  blend  with  the 
sclera.  Mim;te  openings  which  form  a  circle  around  the  the  lamina  cribrosa 
transmit  the  jKisterior  ciliary  vessels  and  nerves.  The  point  of  entrance  of  the 
optic  nerve  is  not  at  the  posterior  pole  or  in  the  visual  axis  of  the  eye,  but  lies 
about  one-tenth  of  an  incli,  or  2.5  nun.,  to  the  nasal  side  of,  and  slightly  below, 
it.  As  this  nerve  passes  through  the  sclera  it  is  constricted,  and  instead  of  passing 
as  a  compact  bundle,  it  is  broken  up  into  fasciculi  which  separatel}^  pierce  the 
fibrous  lamina  mentioned — the  lamina  cribrosa.  The  lamina  has  an  opening  in 
the  center  larger  than  tlie  perforations  produced  by  the  individual  nerve  bundles; 
this  is  called  the  porus  opticus,  and  transmits  the  arteria  centralis  retinae. 

Except  at  the  entrance  of  tlie  optic  nerve  and  the  sclero-corneal  junction,  the 
sclerotic  is  but  feebly  attached  to  the  subjacent  vascular  coat.  Its  innermost 
layer — whicli,  on  account  of  its  deep  color,  is  called  the  lamina  fusca — is  in 
relation  with  the  vascular  coat,  to  which  it  is  attached  by  a  layer  of  loose  connec- 
tive tissue  called  llic  htniiiid  stipraclinroiden. 

The  cornea  is  tlie  circular  anti'rior  window  of  the  eyeball,  and  comprises 
about  one-sixth  of  tlic  eircumfereiuv  of  tlie  glol)e.  It  is  perfectly  transparent,  and 
is  somewliat  tliinut-r  at  its  center  than  at  its  periphery.  Its  ti-ans|iarcncv  is  lost  in 
interstitial  keratitis  (inflammation  of  the  corneal  ti.ssue),  which  is  frequently 
caused  by  syphilis.     It  is  more  highly  convex  than  the  remainder  of  the  eyeball, 


THE  EYEBALL.  363 

and  conseqiu'utly  forms  part  uf  a  smaller  splu're  than  does  the  sclera,  and  hence 
projects  further  than  dues  the  latter.  The  stvideiit  can  reailily  prove  this  fact 
hy  closing  his  tiw  ii  eye  and  moving  the  loose  skin  of  the  up[)er  lid  over  the  globe 
witli  his  tinger.  The  cornea  is  })art  of  the  fibrous  coat  of  the  eye,  and  at  its  peri- 
phery is  eontinuous  with  the  sclera.  Owing  to  the  fact  that  the  transition  of  the 
sclera  into  the  cornea  occurs  lirst  on  the  inner  aspect  of  the  former,  the  sclera  seems 
to  overlap  the  cornea  ;  thus  the  margin  of  the  cornea  becomes  beveled  on  its 
external  asjiect  and  the  sclera  on  its  internal  aspect.  This  apparent  overlapping 
being  greater  above  and  below  than  at  the  sides,  the  transverse  diameter  of  the 
cornea  slightly  exceeds  the  vertical.  It  is  in  front  of  the  aqueous  humor,  which  is 
interjiosed  between  it  and  the  iris  and  lens. 

The  cornea  being  convex,  assists  in  bringing  rays  of  light  to  a  focus  upon  the 
retina.  If  the  convexity  of  the  cornea  is  excessive,  the  rays  are  brought  to  a  focus 
before  reaching  the  retina,  and  the  person  suffers  from  near-sightedness  or  myopia. 
If  the  cornea  is  insufhciently  convex,  the  rays  reach  the  retina  before  being 
collected  to  a  focus,  and  the  person  suffers  from  far-sightedness  or  hypermetropia. 
When  the  curvature  of  the  cornea  is  irregular,  the  raj's  of  light  are  not  regularly 
brought  to  a  focus.  The  error  of  refraction  resulting  is  known  as  astigmatism, 
which  may  also  be  produced  b}'  irregular  refraction  in  the  lens. 

The  cornea  consists  of  five  layers  :  the  anterior  epithelium,  the  anterior  limit- 
ing membrane  (membrane  of  Bowman),  the  substance  proper,  the  posterior  limiting 
membrane  (the  membrane  of  Descemet),  and  the  posterior  endothelium. 

The  anterior  epithelium  nnd  jmsterior  endotliclinmof  the  cornea  serve  to  prevent 
absorption  of  li([uid  from  the  tears  and  from  the  anterior  chamber  of  the  eye. 
The  opacity  of  the  corneal  tissue  after  death  is  due  to  imbibition  of  fluid  into  the 
lymph  channels  of  the  cornea.  If  the  anterior  epithelial  layer,  composed  of  the 
conjunctiva,  is  broken,  and  lead  lotions  are  used,  lead  salts  may  be  deposited  and 
impair  the  transparency  of  the  cornea. 

The  substance  proper  (substantia  propria)  is  composed  of  numerous  laminse  of 
modified  connective  tissue,  between  which  are  freely  anastomosing  lymph  channels, 
through  which  it  is  nourished.  Like  the  other  layers  of  the  cornea,  it  contains  no 
lilood-vessels.  These  vessels  end  in  loops  at  its  periphery.  In  interstitial  kera- 
titis these  laminte  are  affected,  and  effusion  into  the  lymph  channels  causes 
haziness  and  loss  of  ti'ansparency  of  the  cornea. 

Ulcers  and  wounds  of  the  cornea,  as  a  rule,  heal  readily,  notwithstanding  the 
absence  of  l)lood-vessels.  Ulcers  may,  however,  perforate  the  cornea.  Perforating 
ulcers  or  wounds  of  the  cornea  allow  the  aqueous  humor  to  escape.  With  the 
stream  of  the  escaping  aqueous  humor  the  pupillary  margin  of  the  iris  may  be 
prolapsed  through  the  opening   in  the  cornea.     Scars  resulting  from   ulcers   or 


3G4  SURGICAL  ANATOMY. 

wounds  of  the  cornea  may  produce  an  opacity  resembling  a  small  puff  of  smoke 
(nebula),  or  a  pearly  white  ojiacity,  which  is  designated  leukoma.  These  opacities, 
if  situated  at  the  center  of  the  cornea,  interfere  with  the  passage  of  light  to  the 
most  sensitive  ])ortion  of  the  retina,  making  it  necessary  to  form  an  artificial 
pupil. 

Abscesses  of  the  cornea  gravitate  between  the  laminte  to  the  lower  jiart  of  the 
cornea,  producing  a  crescentic  collection  called  onyx — because  of  its  resemblance 
to  the  crescents  at  the  roots  of  the  finger-nails.  These  abscesses  should  be  evacu- 
ated early  to  avoid  perforation,  escape  of  the  aqueous  humor,  and  protrusion  of  the 
iris. 

In  elderly  persons  there  is  frequently  seen  an  opacity  of  the  corneal  tissue 
near  the  margin  of  the  cornea;  this  opacity  usually  begins  at  the  upper  part  of 
the  cornea,  and  then  at  the  lower ;  subsequently,  the  extremities  of  the  two  hazy 
crescents  meet,  and  a  complete  arcus  senilis  results.  This  condition  is  due  to 
fatty  or  hyaline  degeneration  of  the  corneal  tissue,  probably  the  result  of  defec- 
tive vascular  supplj". 

In  pannus  the  cornea  appears  to  contain  blood-vessels.  Through  irritation 
from  granular  lids  or  inverted  eyelashes  blood-vessels  grow  into  the  corneal  con- 
junctiva, and  later  may  enter  the  corneal  tissue. 

Staphyloma  of  the  cornea  is  a  bulging  forward  of  a  corneal  scar  and  ad- 
herent iris.  It  is  ])roduced  by  increased  intra-ocular  tension  pushing  forward  the 
iris  and  even  the  lens  against  a  weakened  cornea,  and  causing  repulsive  disfigure- 
ment. 

A  conic  cornea  is  thin,  protnides  further  forward  than  normally,  and  retains 
its  transparency.     As  a  result,  vi.sion  is  imperfect. 

Blood  Supply. — The  blood  supply  of  the  cornea  is  indirectly  derived  from  the 
anterior  ciliary  and  long  posterior  ciliary  arteries.  No  blood-vessels  are  found  in 
the  cornea,  nutrition  being  supjilied  liy  imbibition  of  lymph  into  the  lymph 
channuls  of  the  cornea.  The  lack  of  a  direct  l)lood  supply  accounts  for  the  ten- 
dency of  the  cornea  to  become  inflamed  in  poorly  nourished  persons. 

Nerve  Supply. — The  cornea  receives  a  rich  nerve  supply  from  the  ciliary 
nerves.  Its  nerves  are  merely  axis  cylinders,  and,  therefore,  <lo  not  affect  its  trans- 
parency. From  pressure  on  the  ciliary  nerves  in  increased  intraocular  tension,  as 
in  glaucoma,  the  cornea  is  anesthetized. 

The  Pectinate  Ligament  of  the  Iris. — At  the  corneal  margin  the  fourth  layvr 
of  the  cornea,  the  posterior  limiting  membrane,  breaks  up  into  fi]irilla\  some  of 
whicli  run  into  the  base  of  the  iris.  These  comprise  the  pectinate  ligament  of  the 
iris,  and  bridge  over  the  angle  between  the  cornea  and  the  base  of  the  iris.  This 
ligament  contains  lymph  spaces,  called   the  .spaces  of  Fontana,  whieli  coiiiniunicate. 


PLATE  LXXXVlll. 


Cornea 


Sclera 


Spaces 


f  ciliary  m. 


Circular  fbcrs  of  ciliary  m. 


MERIDIONAL  SECTION  OF  CILIARY  REGION  OF  EYEBALL. 
365 


TllK   KY KHALI,.  367 

on  the  one  hand,  witli  tlie  aiiteridr  chamhiT  ol'  the  eye,  and,  on  the  other,  wiili  tlie 
eanal  of  Sclilenmi. 

Tlie  Vascular  Coat,  or  tlie  uveal  tract,  is  the  middle  coat  of  the  eye.  It  has 
heen  ox[)osed  throuiihuut  liy  the  previous  dissection.  It  consists  of  three  portions  : 
the  most  anterior  }iortion  is  the  iris,  the  perforated  circular  curtain  which  hangs 
in  front  of  tin-  lens  ;  the  next  portion  is  the  ciliary  hody,  which  lies  hehind  (he 
iris  ;  and  (he  (hird,  posterior  and  largest,  is  the  choroid. 

The  iris,  as  previously  stated,  is  the  anterior  portion  of  the  middle  tunic,  and 
is  u  perforated  circular  curtain  interposed  between  the  lens  and  tlie  cornea.  It  is 
attached  oidy  at  its  margin,  Avhere  it  is  joined  to  the  cornea  anteriorly  l)y  means 
of  the  pectinate  ligament  of  the  iris,  and  hy  the  ciliary  body  posteriorly.  The.se 
attachments  are  not  verv  strong ;  consequently,  in  injuries  of  the  eye  the  iris  may 
be  torn  away  from  the  cornea  and  ciliary  body  without  damage  to  either  of  these 
two  structures.  It  is  contractile  and  expansile,  and  floats  in  the  clear  aqueous 
humor,  separating  the  anterior  chamber  of  the  eyeball  from  the  i^osterior  chamber, 
which  communicate  with  each  other  through  the  central  opening  of  the  iris,  called 
the  pupil.  In  the  fetus  the  pupil  is  closed  by  the  pupillary  membrane,  which  dis- 
appears before  birth.  By  change  in  size  of  the  pupil  the  iris  regulates  the  amount 
of  light  admitted  to  the  interior  of  the  eye.  Both  contraction  and  dilatation  of 
the  pupil  are  active  processes,  the  presence  of  circular  and  radiating  muscle  fibers 
having  been  demonstrated.  Near  the  pupil  the  posterior  surface  of  the  iris  is  in 
contact  with  the  lens,  hence  in  iritis  the  iris  may  adhere  to  the  lens,  jiroducing 
posterior  synechia ;  when  the  iris  adheres  to  the  cornea,  anterior  synechia 
results. 

The  iris  receives  much  support  from  contact  with  the  lens ;  consequently, 
when  the  lens  is  dislocated  posteriori}^  or  after  cataract  ojierations,  the  iris  may  be 
tremulous  through  lack  of  support. 

The  Argyll  Robertson  pupil  is  one  which  docs  not  respond  to  stimulation  by 
light,  but  retains  its  power  of  acconmiodation  for  distance.  It  is  a  diagnostic 
sign  in  locomotor  ataxia,  and  has  been  observed  in  cerebral  syphilis,  general 
paralysis  of  the  insane,  and  poisoning  by  carbon  bisulphid. 

The  color  of  the  iris  varies  in  different  individuals,  and  is  largely  depen- 
dent on  the  amount  and  position  of  its  pigment.  In  blue  eyes  the  stroma  of  the 
iris  is  entirely  free  from  pigment,  the  latter  being  confiy,ed  to  the  posterior  pigment 
layer,  from  which  position  it  is  seen  through  the  superimposed  strata  of  the  iris. 
"With  tlie  darker  eyes  the  stroma  cells  of  the  iris  also  acquire  pigment ;  in  light 
gray  eyes  this  is  small  in  amount,  in  brown  eyes  greater,  while  in  the  darkest  eyes 
the  colored  particles  are  very  numerous,  and  sometimes  appear  as  almost  continu- 
ous pigmented  areas;  in  albino  eyes,  on  the. other  hand,  even  the  retinal  jiortion 


368  SURGICAL  ANATOMY. 

of  the  iris  is  devoid  of  pigment  (Piersol).  The  color  of  the  iris  may  be  greatly 
altered  during  inflammation  of  that  structure,  through  effusion  into  the  tissues  of 
the  iris.  The  swelling  tlms  produced  causes  sluggish  movement  of  the  iris,  and 
encroachment  upon  the  pupil. 

Blood  Supply. — This  is  derived  from  the  ciliary  vessels ;  consequently,  iritis 
is  usually  associated  with  choroiditis. 

Nerve  Supply. — The  nerve  supply  of  the  iris  is  derived  from  the  ciliary 
nerves.  The  radiating  muscle  fibers  are  supplied  through  the  lenticular  ganglion 
by  the  sympathetic  nerve,  and  the  circular  fibers  through  the  lenticular  ganglion 
by  the  third  cranial  nerve. 

The  path  for  the  iris  reflex  (that  is,  the  contraction  ami  dilatation  of  tlie  i)upil 
induced  by  variations  in  the  amount  of  light  falling  into  the  eye)  is  along  the 
optic  nerve  and  tract  to  the  geniculate  body,  or  perhaps  the  anterior  pair  of  corpora 
quadrigemina,  thence  to  the  nucleus  of  the  motor  oculi,  along  the  latter  nerve  to 
the  ciliary  ganglion,  and  then  through  the  ciliary  nerves  to  the  iris.  Interference 
with  this  path  by  lesions  in  the  optic  nerves  or  tracts  or  in  the  central  nervous 
system  leads  to  disturbances  which  the  clinician  utilizes  for  diagnostic  purposes. 

Coloboma,  or  a  cleft  of  the  iris,  is  the  most  common  congenital  defect  of  the 
iris;  it  is  usually  situated  below  tlie  pujiil,  and  is  due  to  persistence  of  the 
choroid  cleft  of  the  embryo. 

Aniridia,  or  absence  of  the  iris,  is  a  rare  defect ;  it  is  usually  bilateral. 

The  ciliary  body,  (,>r  cyclon,  the  intermediate  portion  of  the  middle  tunic  or 
uveal  tract,  is  composed  of  two  portions — the  ciliary  muscle  and  the  choroid 
portion  or  ciliary  processes.  It  extends  from  the  posterior,  or  ciliary,  margin  of 
the  iris  to  a  point  opposite  the  ora  serrata  of  the  retina.  In  meridional  sections  of 
the  eyeball  it  is  triangular.  The  outer  side  of  the  triangle  is  formed  by  the  ciliary 
muscle,  and  is  in  contact  with  the  sclera ;  the  postero-internal  side  is  directed 
toward  the  vitreous  chamlier  of  the  eyeball,  and  contains  tlie  ciliary  i)rocesses ;  the 
anterior  side  is  directed  toward  the  aqueous  chamber,  and  gives  attachment  to  the 
margin  of  the  iris  at  about  its  middle.  The  ciliary  body  is  well  supplied  with 
branches  from  the  ciliary  vessels  and  nerves.  Inflammation  spreads  rapidly  from 
it  to  the  iris,  choroid,  retina,  and  cornea.  It  is  called  the  dangerous  area  of 
the  eye,  because  traumatic  inflammation  of  the  ciliary  l)ody  in  one  eye  may  be 
followed  by  sympathetic  oj)htiialniia  beginning  in  the  ciliary  body  of  the  other 
eye.     This  is  supposed  by  some  to  be  due  to  the  rich  nerve  sn]iply  of  that  region. 

The  ciliary  muscle  foi'ms  a  conspicuous  white  band  between  the  choroid  and 
the  iris,  and  lieijiiid  the  sclero-corneal  junction.  It  bears  on  its  inner  surf^ice  the 
cdiary  pi'ocesses.  In  cross  section  of  tiic  ciliary  liody  or  longitudinal  section  of  the 
eyeball  it  appears  as  a  triangular  band   of  muscle  libers.     The  shorter  anterior 


PLATE  LXXXIX. 


Vena  vorticos 


Meridional  fibers  of  ciliary  in. 

Circular  fibers  of  ciliary  m. 
Conjunctiva 

Anterior  chamber 


Lamina  supracHoroidea 


Pupil 


S—  11-24 


EXTERNAL  AND  MIDDLE  COATS  OF  THE  EYEBALL, 
369 


PLATE  XC. 


Ciliary  processes. 


Suspensory  ligament  of  lens 


Posterior  surface  of  lens 


CILIARY  REGION  (FROM  LION'S  EYE  IN   MUSEUM  OF  UNIVERSIT/  OF  PENNSYLVANIA). 


?,72 


THE  EYEBALL.  373 

silk'  of  tlic  trian^-le  exteiuls  IVuin  the  sclcro-eonu'al  jviiu'tion  toward  the  ciliary 
processes;  ami  at  the  angle  of  juiietiuii  of  the  other  two  sides  it  joins  the  anterior 
margin  of  the  choroid.  It  consists  of  fasciculi  oi'  nuisealar  tissue,  the  interstices 
of  wliich  are  tilled  with  similar  strands  of  connective  tissue.  The  muscular 
tissue,  like  all  similar  structure  in  the  eyeball,  is  composed  of  involuntary  muscle 
fibers  arranged  in  two  sets — meridional  and  circular.  The  meridional  or  longi- 
tudinal muscle  fibers  arise  from  the  sclera  and  the  sclero-corneal  junction,  ])ass 
backward,  and  are  inserted  into  the  choroid  opposite  the  ciliary  processes.  The 
circular  muscle  fibers,  or  ring  muscle  of  Jliiller,  are  placed  internal  to  the  meri- 
dional fibers  in  the  ciliary  body,  and  encircle  the  attached  margin  of  the  iris. 

Blood  Supply. — The  ciliary  muscle  and  ciliary  body  are  supplied  with  blood 
from  the  long  jiosterior  ciliary  and  anterior  ciliary  arteries. 

Nerve  Supply. — The  ciliary  body  and  ciliary  muscle  depend  upon  the  long 
and  short  ciliary  nerves  for  their  nerve  supply,  the  ciliary  muscle  being  supplied 
by  fibers  of  these  nerves  derived  from  the  third  cranial  nerve. 

Action. — The  ciliary  muscle  jiossesses  the  function  of  accommodation,  and 
permits  variation  in  the  degree  of  convexity  of  the  lens  to  enable  the  rays  of  light 
to  reach  a  focus  on  the  retina.  The  ciliary  muscle  pulls  upon  the  ciliary  i)rocesses 
and  relaxes  the  suspensory  ligament  of  the  lens  ;  lessened  tension  upon  this  liga- 
ment relaxes  the  capsule  of  the  lens,  and  allows  the  anterior  surface  of  the  lens  to 
bulge  forward.  In  the  hyperopic  or  long-sighted  eye,  in  wliieh  the  antero-i)osterior 
axis  of  the  eyeball  is  too  long,  the  ciliary  muscle  is  overworked  in  endeavoring  to 
bring  the  rays  of  light  from  near  objects  to  a  focus  upon  the  retina  ;  consequently, 
in  hj'peropia  the  ciliary  muscle,  and  especially  the  ring  muscle  of  Miiller,  is  hj'per- 
trophied.  After  a  severe  illness,  or  frequent  and  long-continued  periods  of  read- 
ing, this  muscle  is  unable  to  pei'form  the  recjuired  amount  of  work,  and  the  hyper- 
metropic state  ensues,  which  should  be  relieved  by  a  convex  lens.  As  the  third 
cranial  nerve  supplies  the  internal  rectus  muscle  as  well  as  the  the  ciliary  muscle, 
and  does  not  supply  the  external  rectus  muscle,  convergent  squint  is  frequently 
associated  with  hypermetrojiia.  A  properly  selected  convex  lens  removes  the 
cause  of  the  spasm  of  the  internal  rectus  muscle,  and  the  strabismus  disappears. 

Dissection. — Secure  a  fresh  eye,  and  with  a  sharp,  thin-bladed  knife  or  a  pair 
of  scissors  cut  the  globe  in  half  slightly  anterior  to  the  equator.  Scoop  out  the 
jelly-like  vitreous,  leaving  intact  the  lens  and  its  attachments.  Place  the  bowl- 
like preparation,  thus  produced,  in  a  shallow  tray  containing  dilute  alcohol,  and 
wash  out  the  pigment  with  a  small  camel's-hair  pencil.  A  clear  posterior  view  of 
the  ciliary  processes  will  then  l)e  secured.  To  see  them  from  in  front  another 
dissection  should  be  made.  Tiie  cornea  may  be  removed  by  making  a  circular 
incision  just  anterior  to  the  sclero-corneal  junction.     Four  meridional  incisions 


374  SURGICAL  ANATOMY. 

should  be  made  through  the  sclera  and  carried  backward  to  about  one-quarter  of 
an  inch  from  the  posterior  pole  of  the  eye.  The  flaps  thus  formed  should  be 
pinned  back,  and  the  whole  preparation  placed  in  dilute  alcohol  held  in  a  wax- 
or  cork-lined  tray.  With  delicate  forceps  and  scissors  the  iris  is  then  removed, 
when  an  anterior  view  of  the  ciliary  processes  may  be  had. 

The  ciliary  processes  are  some  seventy  or  eighty  irregular  projections  from 
the  internal  surface  of  the  ciliary  body.  They  are  longitudinal  folds  of  the 
forward  continuation  of  the  choroid.  Their  broader  extremities  are  directed 
forward  and  form  a  circle, — corona  ciliaris, — which  gives  attachment  to  the  suspen- 
sory ligament  of  the  lens.  Toward  the  posterior  part  of  the  ciliary  body  they 
become  less  prominent  and  subdivide,  the  inner  surface  of  the  ciliary  body  here 
being  almost  smooth  and  forming  the  orbiculus  ciliaris.  The  ciliary  processes  are 
the  most  vascular  portion  of  the  eyeball ;  like  the  choroid,  they  are  composed  of 
a  connective-tissue  stroma,  pigment,  and  numerous  blood-vessels.  By  osmosis  from 
the  blood-vessels  of  the  eyeball  the  acjueous  humor  is  supposed  to  be  replenished. 
As  the  iris  and  the  anterior  portion  of  the  ciliary  body  are  continuous  and  their 
blood-vessels  are  in  free  communication,  iritis  seldom  exists  witliout  cyclitis ;  hence 
the  resultant  disease  is  called  irido-cyclitis. 

The  choroid  proper  extends  from  the  posterior  termination  of  the  ciliary  body 
to  the  optic  nerve,  bj'  which  it  is  pierced.  It  is  found  in  the  posterior  portion  of 
the  globe,  like  the  sclera,  and  consists  mainly  of  blood-vessels,  areolar  tissue,  and 
pigment.  Externally,  it  is  in  relation  with  the  sclerotic  coat,  to  which  it  is 
connected  by  its  outermost  layer — the  lamina  suprachoroidea ;  internally,  it  is  in 
contact  with  the  pigment  layer  of  the  retina. 

It  is  composed  of  four  layers — viz.,  the  lamina  suprachoroidea,  the  layer 
containing  large  vessels,  the  chorio-capillaris,  and  the  lamina  vitrea.  Its  outer 
layer,  the  lamina  suprachoroidea,  is  in  immediate  contact  with  the  sclera,  and  is 
composed  of  loose  areolar,  nonvascular  tissue  containing  pigment.  This  layer 
is  so  loosely  connected  with  the  lamina  fusca  of  the  sclera  that  extensive  hemor- 
rhages may  occur  between  the  sclera  and  choroid  after  traumatism  of  the  eye. 
The  third  and  fourth  laj^ers  are  vascular  in  character.  The  third  is  the  layer  of 
choroid  stroma,  and  contains  large  blood-vessels.  The  most  conspicuous  of  these 
vessels  are  the  four  venx  vorUcosie,  each  of  which  is  formed  liy  numliers  of  veins 
converging  at  one  point  and  forming  a  whorl.  They  are  located  at  eciuidistant 
points  along  the  equator  of  the  eyeball,  and  to  them  the  small  veins  converge, 
returning  the  blood  from  the  whole  uveal  tract.  The  chorio-capillaris  is  the  inner 
vascular  layer,  and  is  composed  of  capillary  Idood-vessels.  The  lamina  vitrea, 
vitreous  or  glassy  lamina,  is  the  fourth  or  internal  layer.  It  supports  the  retinal 
pigment,  whicli  usually  adlieres  to  it  when  tlie  retina  is  removed. 


PLATE  XCI. 


Scle 


Choroid 


Vena  vorticosa 


CILIARY  NERVES, 
376 


PLATE  XCII. 


Long  posterior  ciliary  a 
Long  posterior  ciliary  n 


Vena  vorticosa  Chorio-capillaris 


Circulum  iridis  rtiajor 
Conjunctiva 


Short  posterior  ciliary  a 
Short  posterior  ciliary  n. 


Cornea 


Circulunn  iridis  minor 
Anterior  ciliary  v. 

Anterior  ciliary  a. 


CILIARY  ARTERIES. 
377 


THE  EYEBALL.  379 

The  choroid  contains  so  much  jiignient  that  it  is  one  of  the  few  structures 
affected  hy  primary  melanotic  sarcoma. 

Tlie  ciliary  nerves  have  two  sources  of  origin — the  long  ciliary  nerves  arise 
from  the  nasal  lirancli  of  the  ophthalmic  nerve,  and  the  short  ciliary  nerves 
spring  from  the  lenticular  ganglion.  They  pierce  the  sclera  around  the  optic 
nerve,  and  pass  forward  between  the  sclera  and  the  choroid  ;  at  the  posterior  jiart 
of  the  globe  thej'  groove  the  inner  surface  of  the  sclera  and  are  intimately  attached 
to  it.  They  pass  forward  to  the  ciliary  body,  where  they  break  up  to  form  a 
plexus,  from  whicli  fil>ers  are  distributed  to  the  ciliarj'  muscle,  the  iris,  and  the 
cornea.  Compression  of  these  nerves  against  the  resisting  sclera  in  increased 
intra-ocular  tension,  as  in  glaucoma,  causes  intense  pain  in  the  eyeball  and 
anesthesia  of  the  cornea. 

The  ciliary  arteries  consist  of  the  short  posterior,  long  posterior,  and  anterior. 
The  short  posterior  ciliary  arteries  are  from  twelve  to  twenty  in  number ;  they 
pierce  the  sclera  around  the  optic  nerve,  and  are  distributed  to  the  choroid.  The 
long  posterior  cilia nj  arteries  pierce  the  sclera  just  external  to  the  circle  formed  by 
the  perforations  for  the  short  ciliary  arteries,  and  run  forward  in  the  choroid. 
In  the  ciliary  body  around  the  attached  margin  of  the  iris  they  anastomose  with 
the  anterior  ciliary  arteries.  These  inosculations  form  the  circulum  iridis  major; 
branches  from  this  circle  enter  the  iris,  and  at  the  outer  margin  of  the  sphincter 
muscle  of  the  iris  anastomose  and  form  the  circulum  iridis  minor. 

The  anterior  ciliary  arteries  are  eight  in  number,  two  arising  from  each  of  the 
arteries  which  supply  the  rectus  mu.scles.  They  pierce  the  sclera  near  the  sclero- 
corneal  junction,  and  enter  into  the  circulum  iridis  major.  The  ciliary  arteries 
and  nerves  are  ahso  described  with  the  orbit. 

The  veins  which  have  their  origin  in  the  middle  coat  of  the  eyeball  are  the 
venae  vorticosse  and  the  anterior  ciliary  veins.  The  venae  vorticosee  have  been 
previously  described  with  the  choroid  and  the  orbit.  The  anterior  ciliary  reins 
arise  from  small  veins  in  the  ciliary  muscle,  and  pierce  the  sclera  near  the  margin 
of  the  cornea,  receiving  A'eins  connected  with  the  canal  of  Schlemm.  They  also 
receive  conjunctival  and  episcleral  veins,  and  empty  into  the  veins  which  accom- 
pany the  arteries  to  the  rectus  muscle. 

DisSECTiox. — The  choroid,  ciliary  body,  and  iris  should  be  carefully  stripped 
from  that  eyeball  in  which  they  were  exposed.  This  should  be  done  under 
diluted  alcohol,  and  when  completed,  the  retina  will  be  seen.  If  a  portion  of  the 
detached  choroid  is  inspected,  on  its  inner  surface  irregular  black  patches  -will  be 
observed.  These  are  fragments  of  the  pigment  layer  of  the  retina  which  have 
become  detached  on  account  of  their  firm  adhesion  to  the  lamina  vitrea  of  the 
choroid. 


380  SURGICAL  ANATOMY. 

The  Retina,  the  third  and  innermost  coat  of  tlie  eye,  is  the  nervous  tunic. 
It  is  the  end  organ  of  the  optic  nerve  speciahzed  for  the  function  of  vision.  Mor- 
phologically, it  extends  from  the  point  of  entrance  of  the  optic  nerve  at  the 
foramen  sclerse  to  the  free  margin  of  tlie  iris.  It  consists  of  three  parts :  The 
posterior  portion  is  situated  between  the  choroid  and  the  vitreous  body,  and 
extends  from  the  optic  nerve  entrance  to  the  ciliary  body,  where  the  retina 
suddenly  becomes  thin  along  an  irregular  line,  thus  forming  the  ora  serrata. 
This  posterior  jKirtion  is  called  the  optic  part,  or  pars  optica  retinae,  and  tci-min- 
ates  at  the  ora  serrata.  The  next  portion,  the  ciliary  part,  or  the  pars  ciliaris 
retinae,  lines  the  inner  surface  of  the  ciliary  body,  extending  as  far  forward  as 
the  insertion  of  the  iris.  The  anterior  portion  lines  tlie  internal  surface  of  the 
iris,  and  is  called  the  pars  iridica  retinae.  The  pars  optica  retinse  is  the 
only  part  which  has  much  visual  function  ;  because  the  pars  ciliaris  and  pars 
iridica  retinae  are  mainly  continuations  of  the  pigment  layer  beyond  tlie  ora 
serrata,  at  which  the  highly  specialized  layers  of  tlie  retina  suddenlj-  diminish  in 
thickness. 

When  viewed  from  the  interior,  a  circle  is  seen  at  the  point  of  entrance  of 
the  optic  nerve.  This  is  called  the  02:)tic  disc.  It  is  sometimes  called  the  j^orus 
opticus,  but  this  name  should  be  applied  only  to  the  foramen  in  the  lamina  crib- 
rosa  traversed  by  the  central  artery  of  the  retina.  This  disc  lies  one-tenth  of  an 
inch  or  two  and  one-half  millimeters  to  the  inner  side  of  the  posterior  pole  of  the 
eye.  As  this  is  the  blind  spot  of  the  retina,  it  is  placed  outside  of  tlie  direct  line 
of  vision.  Exactl}'  in  the  center  of  the  retina,  at  the  posterior  pole,  and  in  the 
direct  line  of  vision,  a  small  j-ellow  spot,  called  the  macula  lutea,  is  seen  in  a  fresh 
eye ;  the  depression  in  the  center  of  the  macula  lutea  is  termed  the  fovea  centralis. 
The  macula  lutea  is  the  point  at  which  vision  is  most  acute.  For  that  reason  it  is 
situated  in  a  line  with  the  centers  of  the  lens,  pupil,  and  cornea,  so  that  it  receives 
the  rays  of  light  brought  to  a  focus  by.  the  lens.  Eays  from  other  points,  passing 
through  the  lens,  strike  other  portions  of  the  pars  optica  retina^  and  produce 
collateral  vi.sion,  which  is  less  distinct. 

The  retina  is  derived  from  the  two  layers  of  the  optic  cup,  which  is  an 
extension  of  the  anterior  cerebral  vesicle  and  is,  therefore,  ectodermic  in  origin. 
The  outer  layer  of  the  cup  remains  as  the  pigment  layer  of  the  retina,  while  the 
inner  layer  gives  rise  to  the  remaining  and  more  specialized  portion  of  it.  During 
life  the  inner  layer  is  ]iink  and  transparent ;  but  after  deatli  it  becomes  hazy  and 
opaciue. 

Blood  Supply. — The  blood  suii])ly  of  the  retina  is  derived  partly  from  the 
arteria  centralis  retime,  which  can  be  seen  entering  the  ej'e  at  the  optic  disc.  It 
gives  off  an  asct'iiding  and  a  descending  branch,  each  of  which  has  a  small  nasal 


PLATE  XCII 


Retinal  artery 


Retinal  vein 


Macula  lutea 


Optic  disc 


RETINA  OF  POSTERIOR  ONE-HALF  OF  RIGHT  EYEBALL  (ENLARGED). 

381 


PLATE  XGIV. 


Canal  of  Schle 
Conjunctival  v 


Anterior  ciliary 


Central  vein  of  retina_ 


Conjunctival  a. 

Anterior  ciliary  a. 


Long  posterior  ciliary  a. 


Short  posterior  ciliary  arteries 


artery  of  retina 


BLOOD-VESSELS  OF   EVEBALl   (AFTER  LEBER). 
384 


THE   KY KHALI..  385 

branch.  Like  the  vessels  oi'  the  brain,  lungs,  etc.,  its  branches  are  end  arteries, 
not  anastoniosint;-  in  the  substance  of  the  retina  with  each  otberor  witli  the  ciliary 
arteries.  Pi'dliably  the  greater  portion  of  tlie  nourishment  of  the  retina  is  derived 
from  the  iiostcrinr  ciliary  vessels,  through  the  chorio-capillaris  of  tlu'  choroid. 

The  retinal  veins  converge  to  form  two  ves.sels  which  enter  the  optic  nerve  at 
the  optic  disc,  aiul  soon  join  to  form  one  vena  centralis  retina;,  which  pursues  a 
course  in  the  nerve  corresponding  to  that  of  the  artery. 

Dissection. — The  metliod  of  Anderson  Stuart  will  be  found  the  most  satis- 
factory for  studying  the  vitreous  body  and  lens.  A  perfectly  fresh  eyeball  should 
not  be  used  :  it  should  be  kept  from  one  to  three  daj's  before  being  utilized, 
according  to  the  season  of  the  year.  The  three  tunics  are  divided  at  the 
ecpiator  and  turned  back.  This  is  done  carefully  and  over  a  vessel  of  diluted 
alcohol,  into  which  the  so-called  "  eye  kernel,"  composed  of  the  vitreous  body 
and  lens,  is  allowed  to  fall.  The  "  eye  kernel "  is  then  placed  in  a  strong 
picrocarmin  solution  for  a  few  minutes,  and  when  removed,  it  should  be  well 
washed.  By  this  method  the  hyaloid  membrane,  the  lens  capsiile,  and  the  zone 
of  Zinn  are  stained  red.  If  tlie  solution  is  shaken  gently,  the  coloring  matter  may 
enter  the  hyaloid  canal,  which  may  thus  be  recognized. 

The  Vitreous  Body  is  a  soft,  gelatinous,  perfectly  transparent  substance, 
composed  of  semi-solid  connective  tissue.  It  occupies  the  posterior  cavity  or 
vitreous  chamber  of  the  glol>e.  The  vitreous  chamber  is  bounded  behind  and 
laterally  by  the  retina,  and  in  front  by  the  lens  and  the  zone  of  Zinn.  The 
vitreous  body  consists  of  the  vitreous  substance,  inclosed  b}^  the  hyaloid  membrane, 
except  anteriorly,  where  the  vitreous  substance  comes  into  dii'i'ct  contact  with 
the  lens  capsule,  receiving  the  lens  into  a  depression,  the  patellar  fossa  of  the  vit- 
reous body.  It  has  an  indistinctly  reticulated  structure,  and  may  contain  small 
corpuscular  bodies  which  occasionally  produce  shadow's  upon  the  retina,  the  so- 
called  musCcB  volitantes.  Running  from  the  optic  disc  to  the  center  of  the 
posterior  surface  of  the  lens  is  a  narrow  canal,  lined  by  a  prolongation  of  the 
hyaloid  membrane,  and  called  the  hyaloid  canal,  canal  of  Stilling,  or  canal 
of  Cloquet.  During  fetal  life  this  canal  transmits  an  artery  to  the  lens,  the 
hyaloid  artery,  and  in  the  adult  contains  the  remains  of  the  supporting  connective 
tissue  or  rarely  an  atroidiied  vessel. 

The  Zone  of  Zinn,  Zonula  of  Zinn,  or  Suspensory  Ligament  of  the  Lens,  is 
the  thickened  portion  of  the  hyaloid  membrane  extending  from  the  ciliary  body 
to  the  lens.  At  the  ora  serrata  tlie  hyaloid  membrane  becomes  attached  to  the 
ciliary  body  and  remains  so  attached  as  far  as  the  peripheral  or  anterior 
ends  of  tlie  ciliary  processes.  From  the  apices  of  the  ciliary  processes  thick 
bamls  of  tlie   hyaloid  menibrane   pass  over  to  the  lens,  going  to  its  ])eriphery  and 


386  SURGICAL  ANATOMY. 

anterior  surface.  The  hyaloid  membrane,  in  this  region,  is  thrown  into  numerous 
folds,  caused  by  the  plications  of  the  choroid  portion  of  the  ciliary  body,  to  which 
it  is  so  closely  apposed.  At  the  ciliary  margin  of  the  ligament  these  folds  become 
converted  into  stiff  fibers,  which  form  two  series.  One  series  consists  of  those 
fibers  which  spring  from  the  apices  of  the  ciliary  processes  ;  the  other,  of  those 
which  spring  from  the  depressions  between  the  processes.  The  former  are  inserted 
into  the  periphery  and  adjacent  jiarts  of  the  posterior  portion  of  the  capsule  of  the 
lens,  arid  the  latter  go  to  the  anterior  surface  of  the  lens,  blending  with  the  super- 
ficial layers  of  the  anterior  portion  of  the  lens  capsule. 

The  lens  is,  in  this  manner,  maintained  in  its  position.  The  tension  of  the 
zone  of  Zinn  is  varied  by  contraction  of  the  ciliary  muscle  ;  when  this  muscle 
contracts,  the  suspensory  ligament  is  relaxed  ;  tlms,  the  lens  is  less  firmly  com- 
pressed, and  by  its  own  elasticity  becomes  more  convex,  and  its  focal  distance  is 
decreased.     This  function  is  known  as  accommodation. 

The  Canal  of  Petit  is  a  narrow  lympliatic  channel  which  encircles  the  margin 
of  tlie  lens,  is  triangular  on  section,  and  is  bounded  in  front  by  the  anterior 
lamina  of  the  suspensory  ligament  of  the  lens,  behind  by  the  hyaloid  membrane, 
and  internally  by  the  capsule  of  the  lens.  It  is  subdivided  into  two  portions 
by  the  fibers  of  the  posterior  lamina  of  the  suspensory  ligament  of  the  lens.  The 
lymph  in  the  canal  of  Petit  is  derived  from  the  ciliary  vessels,  and  is  supposed  to 
supply  nutrition  to  the  lens. 

Dissection. — By  carefully  inserting  a  fine  lilowpipe  into  the  canal  of  Petit  it 
may  be  distended  1)v  air  or  a  colored  fluid.  When  so  dilated,  it  presents  a  series 
of  sacculations,  due  to  the  undulations  in  the  zone  of  Zinn  produced  by  the  ciliary 
processes.  Remove  the  lens  by  cutting  through  the  zone  of  Zinn  Avith  a  pair  of 
scissors. 

The  Crystalline  Lens  is  a  biconvex,  circular-  body,  lying  behind  the  iris  and 
aqueous  humor,  and  in  front  of  the  vitreous  body.  Its  rounded  margin  is  a  sliort 
distance  from,  and  parallel  with,  the  corona  ciliaris  of  the  ciliary  body,  to  which 
it  is  firmly  attached  bj^  the  suspensory  ligament  of  the  lens.  The  center  of  the 
anterior  surface  of  the  lens  is  the  anterior  pole,  and  the  center  of  the  posterior 
surfiice  is  the  posterior  pole.  The  convexity  of  the  anterior  surface  of  the  lens  is 
not  so  great  as  that  of  the  po.sterior  surface.  The  central  jiortion  of  the  anterior 
surface  is  opposite  the  pupil,  and  in  contact  with  the  acpieous  liumor  of  tlie 
anterior  chamber.  At  the  margin  of  this  central  portion  the  lens  is  in  contact 
with  the  posterior  surface  of  the  puinllary  margin  of  the  iris ;  external  to  this 
margin  the  curvature  of  the  lens  carries  it  away  from  the  iris  ;  this  interval 
between  the  lens  and  iris  is  the  posterior  chamber  of  the  eye,  and  is  filled  with  part 
of  the  aqueous  humor.     Posteriorly,  tlie  lens  is  received  into  tiie  i)atel!ar  fossa  of 


PLATE  XCV. 


THE  DARK  AREAS  REPRESENT  THE  LENS,  IRIS,  AND  CILIARY  BODY  AT  REST;  AND  THE  BROAD  OUTLINES  INDICATE 
THE  CHANGED  POSITION  OF  THOSE  STRUCTURES  DURING  ACCOMMODATION  (AFTER  FUDHS). 


EMMETROPIC  EYE. 


388 


MYOPIC  EYE, 


PLATE  XCVI. 


MYOPIC  EYE  WITH  CONCAVE  LENS. 


HYPEROPIC  EYE. 


HYPEROPIC  EYE  WITH  CONVEX  LENS. 


389- 


TUI-:   EYF.BM.L.  391 

tlio  vitrt'iius  lioily.  rcri|ilRTally,  it  is  in  rclatinn  with  the  /.one  of  Ziiiu  inul  tlie 
eaiial  ol'  I'elit. 

The  lens  is  composed  of  the  lens  capsule  and  the  lens  substance.  The 
capsule  of  the  lens  is  the  stront;-,  elastic,  transparent  membrane  which  surrounds 
the  lens  sul)stance.  Tlie  lens  substance  is  a  transparent,  gelatinous  material, 
translucent  in  the  cadaver,  and  composed  of  transparent  fibers  joined  liy  a  trans- 
parent cement.  The  cortex,  nr  peripheral  pDrtinn,  is  soft,  an<l  tlie  central 
portion,  or  nucleus,  is  lirm. 

Dissection. — With  a  sharp  knife  divide  the  anterior  part  of  the  capsule 
of  the  lens,  and  tluii  express  the  lens  substance  through  the  opening  as  one 
squeezes  the  pulp  t)f  a  grape  from  its  skin;  the  capsule  and  lens  substance  can 
now  he  exannned. 

Tile  capsule  of  the  lens  or  the  suspensory  ligament  may  be  ruptured  by 
traumatism,  and  the  lens  escape  mto  the  vitreous  or  aqueous  humor.  If 
the  anterior  portion  of  the  capsule  is  torn,  the  aqueous  humor  will  enter  and 
produce  opacity  of  the  lens.  This  is  done  purposely  in  the  treatment  of  soft 
cataract,  so  that  the  lens  substance  may  be  absorbed  by  the  aqueous  humor. 

In  presbyopia,  or  old-age  sight,  the  jjower  of  accomm<idation  is  diminished 
through  the  loss  of  elasticity  of  the  lens.  This  occurs  between  the  ages  of  forty 
and  fifty  years.  In  an  emmetropic  eye  which  has  become  presbyopic  parallel  raj^s 
come  to  a  focus  on  the  retina,  and  distant  objects  are  easily  seen,  but,  through  loss 
of  accommodation,  near  objects  are  not  discerned  so  readily.  As  hj'^peropic  eyes 
constantly  require  the  function  of  accommodation,  gradual  loss  of  this  function 
causes  them  to  feel  the  effects  of  presbyopia  at  an  earlier  age  than  emmetropic  or 
myopic  eyes.  A  myopic  eye  may  never  sufter  from  the  effects  of  presbyopia, 
because  it  requires  no  accommodation. 

A  cataract  is  a  diminution  in  the  transparency  of  the  cap.sule  or  sul)stance  of 
the  lens.  After  extraction  of  the  cataractous  lens,  much  of  the  refractive  power 
of  tlie  eyeball  is  lost ;  consequently,  highly  convex  glasses  are  recjuired  to  liring  tlie 
rays  of  light  to  a  focus  on  the  retina. 

The  Chambers  of  the  Eyeball  are  two  in  number  in  addition  to  the  vitreous 
chaml)er.  Both  are  in  front  of  the  lens  ;  lioth  are  lymph  spaces  and  contain 
ac^ueous  humor,  and  they  are  separated  from  each  other  by  the  iris. 

The  anterior  chamber  of  the  eye  is  bounded  in  front  l>v  tlie  cornea  and 
behind  by  the  iris  and  that  portion  of  the  li-ns  whii'li  presents  at  the  pupil.  It 
rommunicates  with  tlie  posterior  chamber  tiirough  the  pu])i!.  At  its  external 
angle  it  is  bounded  by  the  pectinate  ligament  of  the  iris.  Tiiis  angle,  which  is 
formed  by  the  peripheral  portions  of  the  cornea  and  iris,  is  called  the  muile  or 
s//)((.s  of  the  anterior  chamber,  or  the  filtration  angle.     Knowledge  of  the  anatomy  of 


392  SURGICAL  ANATOMY. 

the  structures  at  this  angle  is  most  important,  for  it  is  here  that  the  excess  of  the 
aqueous  humor  escaj)es  into  tlie  spaces  of  Fontana,  and  thence  In*  way  nf  {\w  canal 
of  Schlemn  into  the  anterior  ciliary  veins,  thus  reducing  intra-ocuhir  tension. 

Hypopyon  is  a  collection  of  pus  in  the  anterior  chamber  of  the  eye,  and 
arises  from  suppurative  inflammation  of  the  cornea,  iris,  ciliary  body,  and  choroid. 
Pus  passes  from  the  ciliary  body  through  the  pectinate  ligament  of  the  iris  or  the 
attached  margin  of  the  iris  to  reach  the  anterior  chamber,  causing  cloudiness  of 
the  aqueous  humor,  and  its  solid  portion  gravitates  to  the  most  dejsendent  jiart  of 
the  anterior  chamber,  varying  its  position  with  movements  of  the  head.  Hy- 
popyon is  crescentic  in  form,  like  onyx,  but  the  latter  is  stationary. 

The  posterior  chamber  of  the  eye  is  a  circular  space,  triangular  on  cross- 
section,  and  situated  behind  the  iris.  It  is  bounded  in  front  l)y  the  iris; 
behind,  by  the  lens  and  zone  of  Zinn  ;  and  externally,  by  the  anterior  portion  of 
the  ciliary  body.     It  is  limited  internally  l)y  the  jjupillary  margin  of  the  iris. 

The  Lymphatic  System  of  the  Eyeball  contains  no  lymphatic  vessels  except 
tho.se  of  the  conjunctiva,  the  lymph  being  in  spaces.  These  sjjaces  are  divided 
into  an  anterior  and  a  posterior  set. 

The  anterior  lymph  passages  of  the  eye  include  the  lymph  spaces  of  the 
cornea  and  iris,  and  the  anterior  and  [)osterior  chand)ers  of  the  eyeball. 

The  Ujmph  tspaces  of  the  cornea  are  situated  between  the  lamellae  of  the  corneal 
substance.  At  the  periphery  of  the  cornea  the  lymph  flows  into  the  conjunctival 
lymphatic  vessels. 

The  lymph  spaces  of  the  iris  open  into  the  a(|ueous  humor  of  the  anterior 
chamber  of  the  eye  at  small  indentations  called  the  crypts  of  tJie  iris,  and  at  the 
periphery  of  the  iris  communicate  witli  tlie  spaces  of  Fontana. 

Tlie  aqueous  humor  is  composed  of  lymph  situated  in  the  anterior  and  pos- 
terior chambers  of  the  eye.  It  is  secreted  in  the  posterior  chamber  from  the 
plexus  of  vessels  in  the  ciliary  body,  and  partly  from  the  vessels  in  the  posterior 
surface  of  the  iris.  The  aqueous  humor  passes  from  the  posterior  cliamber 
through  the  i)uitil  into  the  anterior  c'liambfr  of  tlie  eye,  and  escapes  by  way  of  the 
spaces  of  Fontana,  the  canal  (.if  Scldennri,  and  the  anterior  ciliary  veins. 

The  posterior  lymph  passages  of  tlie  vyc  include  the  hyaloid  canal,  the  peri- 
cJioroid  space,  Tenon's  sjiace,  the  intervagiual  space  of  tlie  oj)tic  nerve,  and  the 
supra-vaginal  space. 

'I'be  Injitloid  raviil,  ov  ccnlral  (■.•uial  ol'  Die  vitreous  body,  extends  from  tlie 
optic  disc  forward  In  (he  postci'ior  jiole  of  Ibe  lens.  In  the  embryo  it  contains  tlie 
hj'aloid  artery,  wbirli  disappears  later,  altbuugji  (ln'  caiiMl  remains  as  a  lymph 
cliainiel  wJiich  is  drained  by  the  intervagiual  si)ace  of  the  optic  nerve. 

The  perichoroid  Jijmph   s^wce,  situated  between  the  choroid  and  the  sclera,  is 


PLATE  XCVII, 


Lens 


Suspensory  I 


Cornea 


Anterior  chamber 


terior  chamber 


JULAR  POSTERIOR  SYNECHIA. 
394 


THE   EYE  BALL.  395 

continued  along  the  vessels  of  the  choroid  and  especially  along  the  veno3  vorticosae. 
Its  lymph  escapes  into  Tenon's  space  hy  [lerf'o rations  in  the  sclera  around  the  veufe 
vortieosie. 

Tenon's  space,  situated  between  the  sclera  and  Tenon's  capsule,  drains  the  \k'vi- 
choroid  spat'c,  and  opens  into  the  supra-vaginal  space. 

The  iidcvcagimd  lijtnph  space  is  situated  between  the  dural  and  pial  sheaths  of 
the  optic  nerve,  and  is  subdivided  into  a  subdural  and  subaracinioid  space  by  the 
extension  of  the  arachnoid  membrane  of  the  brain  along  the  optic  nerve.  It  opens 
into  the  subdural  and  subarachnoid  spaces  of  the  brain. 

The  suprar-vaginal  lymph  space  is  situated  between  the  dural  sheath  of  the 
optic  nerve  and  the  posterior  extension  of  Tenon's  capsule. 

The  greater  portion  of  the  lymph  of  the  eyeball  escapes  by  way  of  the 
chambers  of  the  aqueous  humor,  spaces  of  Fontana,  canal  of  Schlemm,  and  ante- 
rior ciliary  veins ;  consequently,  any  obstruction  in  the  anterior  lymph  channels 
causes  increased  intra-ocular  tension.  Such  obstruction  occurs  in  annular  posterior 
synechia,  in  which  tlie  whole  pupillary  margin  of  the  iris  is  adherent  to  the  ante- 
rior surface  of  the  capsule  of  the  lens,  and  prevents  the  lymph  of  the  posterior 
chamber,  which  is  derived  from  the  ciliary  vessels,  from  entering  the  anterior 
chamber.  The  pressure  thus  produced  in  the  posterior  chamber  causes  the  peri- 
pheral portion  of  the  iris  to  project  forward  against  the  cornea,  obliterating  the 
tiltration  angle,  or  sinus  of  the  anterior  chamber,  and  preventing  escape  of  Ij'mph 
from  the  anterior  chanrber  of  the  ej'eball.  In  this  manner  the  serious  disease 
of  the  eye,  glaucoma,  which  is  characterized  by  increased  intra-ocular  tension,  is 
produced.  Glaucoma  also  develops  from  conditions  not  so  readily  demonstrable, 
as  hypersecretion  of  lymph,  and  other  causes  of  retention  of  lymph,  in  the  eye- 
ball. 

In  emmetropia,  or  normal  vision,  parallel  rays  of  light  or  those  from  distant 
objects  are  l)rought  to  a  focus  on  the  retina  when  the  eye  is  at  rest,  and  divergent 
rays  or  those  from  near  objects  do  not  reach  a  focus  on  the  retina  without  some 
exercise  of  the  function  of  accommodation.  Normal  vision  occurs  in  an  eye 
whose  axis,  or  sagittal  diameter,  is  of  the  normal  length,  and  whose  media  pos.sess 
the  proper  refractive  index. 

In  hyperopia,  hypermetropia,  or  far-sightedness,  the  axis,  or  sagittal 
diameter  of  the  eye,  is  usually  too  short,  although  liyi)eropia  may  be  due  to 
absence  of  the  lens,  decreased  convexity  of  the  refracting  .surfaces  of  the  eye,  or 
diminished  jiower  of  refraction  in  tlu-  refractive  media  of  the  eye.  The  result  is 
that  when  the  ciliary  muscle  is  at  rest,  parallel  rays  of  light  or  those  from  distant 
objects,  and  divergent  rays  or  those  from  near  objects,  come  in  contact  with  the 
retina   before  being  brought  to  a  focus,  forming  circular  ditiusion  of  the  light 


396  SURGICAL  ANATOMY. 

and  a  blurred  image.  The  ciliarj-  muscle  compensates  for  the  defect  by  contract- 
ing and  allowing  increased  convexity  of  the  lens ;  but  the  severe  strain  causes 
local  and  remote  disorders,  and,  on  account  of  failure  of  the  muscle  to  jserform 
the  work  required,  reading  becomes  difficult.  The  defect  is  corrected  by  converg- 
ing the  rays  with  convex  glasses. 

In  myopia,  w  near-sightedness,  the  antero-posterior,  or  sagittal,  diameter  is 
too  long,  and  parallel  rays  of  liglit  are  brought  to  a  focus  in  front  of  the  retina, 
so  that  distant  objects  are  indistinct  because  the  image  is  blurred.  Divergent 
rays  or  those  from  near  objects  at  a  certain  distance  are  brought  to  a  focus  upon 
the  retina.  Myopia  occasionally  results  from  increased  refractive  power  of  the 
lens;  when  this  occurs  in  an  old  i)erson,  second  sight  is  {produced  and  convex 
glasses  may  be  discarded.  As  there  is  no  mechanism  in  the  eye  which  can  com- 
pensate for  the  defect,  and  the  patient  can  see  near  oljjects,  continued  ej'e  strain 
may  cause  more  serious  disease  of  the  myopic  eye.  The  defect  is  corrected  b}' 
concave  glasses  whieli  cause  the  I'aysto  diverge. 

Exenteration  of  the  orbital  contents  is  performed  for  malignant  disease. 
The  external  canthus  is  split,  and  the  orbital  contents,  including  the  periosteum, 
are  all  removed  except  at  the  apex  of  the  orbit. 

Evisceration  of  the  eyeball  is  performed  in  staphyloma  of  the  cornea  and  dis- 
figuring leukoma.  Tlie  cornea  is  circumcised  at  the  .sclero-corneal  margin,  and  all 
the  contents  of  the  globe  and  the  middle  and  internal  coats  of  the  eyeball  are  care- 
fully removed,  leaving  the  sclera  intact.  The  opening  is  enlarged  vertically  and 
a  glass  ball  is  inserted  into  the  cavity  of  the  eye.  The  sclera  is  stitched  vertically 
over  the  glass  ball  and  the  conjunctiva  transversely.  After  the  wound  heals,  an 
artificial  shell  may  he  inserted  over  the  stump. 

Enucleation  or  excision  of  the  eyeball. — The  eyelids  are  separated  with  a 
speculum,  and  tlie  ocular  conjunctiva  is  divided  close  to  and  entirely  around  the 
cornea.  The  conjunctiva  and  capsule  of  Tenon  are  pushed  backward  over  the 
eye.  The  rectus  muscles  are  grasped  witli  forceps  at  their  insertions  and  divided 
l)ack  of  the  forceps.  The  globe  is  drawn  forward  and  inward,  and  the  optic 
nerve  and  adjoining  structures  are  divided  with  scissors  along  the  outer  side  of  the 
eyeball.  The  eye  is  then  drawn  out  of  its  socket,  and  the  remaining  adherent 
tendons  and  other  structures  are  severed.  The  cavity  is  irrigated  with  cold  sterile 
water,  an<l  the  sluni]is  nt'  tlic  rectus  nniscle  are  sutured  together.  The  wound  is 
'cleansed,  and  a  sterilized  dressing  applied. 


PLATE  XCVIII, 


Heir, 


Fossa  of  hel 


Darwin's  tubercle 


Antihel 


Concha 


Fossa  of  antihelix 


Tragus 


incisura  intertragica 


Antitragus 

Lobule 


PINNA, 
398 


THE   ORU.-L\    OF  UEAliLM!.  399 

THE  (>I!(;AX  of  IIEAUING. 

The  organ  of  iK'ariiiu-  consists  of  tln\"c  jiovtions — tlio  external,  middle,  ai)d 
internal  ear.  Tlie  External  Ear  ("niiu'isi's  thr  nuride  or  ]iiinia  and  tlie  meatus 
auilitorius  externns  ;  the  former  is  of  hul  sh^lit  im|)()rtance  physiologieallv  ;  the 
latter  is  the  eanal  whieh  leads  inward  to  the  tympanic  memhrane.  The  Middle 
Ear  is  eomjiosed  of  tlie  tympamim.  the  mastoid  antrum,  and  the  mastoid  cells. 
The  tymjianum,  an  air  chandler,  eon]munii'ate.s  with  the  naso-pharynx  hy  means 
of  the  Eustachian  tuhe,  and  contains  a  chain  of  movable  bones — the  auditory 
ossicles.  The  mastoid  antrum  and  mastoid  cells  are  air  chambers  accessory  to 
the  tympanum.  The  Internal  Ear,  or  Labyrinth,  is  made  uji  of  a  complex 
arranj^ement  of  cavities ;  it  contains  a  fluid, — the  perilymph, — together  with  a 
membranous  cast  of  the  bony  structures  known  as  the  membranous  labyrinth  ; 
the  latter  contains  the  endolymph,  and  within  it  are  the  specialized  neuro-epithe- 
lial  cells  and  the  terminations  of  the  auditorv  nerve. 


THE  EXTEItNAL  EAR. 

The  Pinna  consists  of  a  pliable  framework  of  yellowy  elastic  cartilage  covered 
with  integument.  The  external  surface  is  concave,  and  conducts  the  .sound  waves 
to  tiie  external  auditory  meatu.s,  yet  accidental  ov  intt'utional  amputation  of  the 
piinia  causes  but  sliglit  diminution  in  acuteness  of  hearing.  The  outer  concave 
surface  presents  a  number  of  elevations  and  dejiressions.  The  helix  is  the  in- 
curved border  of  the  pinna.  At  the  free  border  of  the  helix  there  is  often  to  be 
seen  a  more  or  less  prominent,  rather  triangular  projection,  known  as  the  Dar- 
winian tubercle ;  it  is  analogous  to  the  pointed  tip  of  the  ear  of  quadrupeds. 
The  fossa  of  the  helix  is  the  groove  formed  liy  the  inward  curvature  of  the  helix. 
In  front  of  the  helix,  and  i-unning  parallel  with  it,  is  a  rounded  prominence,  the 
antihelix,  which  divides  anteriorly  and  above  into  two  jxirtions  inclosing  the  fossa 
of  the  antihelix  (fossa  scaplioidca).  The  antihelix  curves  around  a  large  con- 
cavity,— the  concha, — which  leads  to  the  external  auditory  meatus.  Anterior 
to  the  concha  is  a  Munt  projection,  the  tragus.  This  is  i-cally  a  jtortion  of  the 
wall  <if  tiie  external  auditorv  meatus,  and  tn  it  a  mnidier  of  stiff  hairs  are  often 
attached.  Opposite  the  tragus  is  a  small  })i'ojectiiin.  the  antitragus ;  lictwccu  the 
two  is  a  notch,  the  incisura  intertragica.  The  lowest  portion  of  the  pinna — the 
lobule — is  devoid  of  cartilage,  and  is  comiKised  of  fibro-areolar  and  adipose  tissue. 
The  lolnile  may  gradually  be  slit  in  two  liy  heavy  ear-rings,  an<l  a  fibrous  or 
keloid  tumor  may  arise  from  the  scar  which  forms  wdiere  the  lobule  has  been 
pierced. 


4UU  SURGICAL  ANATOMY. 

The  pinna  is  developed  in  tlie  embryo  from  six  small  tubercles  wliicii  I'oi-m  at 
the  external  extremity  of  the  first  branchial  cleft.  As  a  result  of  imperfect  fusion 
of  these  tubules  supernumerary  auricles  ov  auricular  fistulas  may  occur  near  the 
external  auditory  meatus.  If  the  orihce  of  one  of  these  fistuliB  is  closed,  a  der- 
moid cyst  of  the  jiinna  forms.  Supcrnunuiai-y  j)iun»  or  auricles  may  also 
develop  at  the  external  extremity  of  the  other  branchial  clefts. 

The  integument  of  the  auricle,  which  is  continuous  with  that  liniun  the 
external  auditory  meatus,  is  thin,  and  contains  sebaceous  glands  and,  in  certain 
situations,  hairs  and  sudoriierous  glands.  The  sebaceous  glands  are  most  al)undant 
in  the  concha,  where  their  orifices  can  often  be  .seen,  filled  with  foreign  matei'ial, 
in  ])ersous  wlio  are  careless  as  to  cleanliness.  Sebaceous  cysts  not  infrequently 
develop  in  the  .skin  of  the  i)inna.  The  integument  is  more  firmlj'  attached  over 
the  concave  surface  of  the  pinna  than  on  the  convex  or  cranial  surface.  Hemor- 
rhagic effusions  beneath  the  skin  or  between  the  cartilage  and  its  perichondrium, 
as  a  result  of  trauma,  are  not  uncommonh'  seen  in  pugilists ;  they  are  known  as 
othci)i(d<imala.  On  account  of  the  close  unicm  between  the  skin  an<l  the  concave 
surface  of  the  pinna,  inflammatory  affections  are  painful  in  this  location.  In 
chronic  gout  subcutaneous  dejiosits  of  sodium  urate,  termed  tophi,  are  found  in  the 
]iiinia. 

The  subcutaneous  tissue  of  the  pinna  forms  a  thin  lamina  almost  dcvuid 
of  fat.  The  lack  of  subcutaneous  fat,  which  affords  protection  from  cold  to  the 
bl(ii)d-vessels,  and  the  exposed  position  of  the  ^linna  account  for  tlie  frequency 
of  frost-bite  in  this  location,  which  occasionall}'  causes  gangrene  of  the  pinna. 

The  yellow,  elastic  cartilage  of  the  auricle,  which  gives  form  to  that  struc- 
ture, presents  several  fissures  and  processes ;  there  is  a  fissure  between  the  origin 
of  the  helix  and  the  tragus  which  is  filled  with  fibrous  tissue.  The  lower  end 
of  the  antihelix  is  divided  into  two  jiarts,  one  of  whieli  terminates  in  a  pointed 
extremity  called  the  processus  caudatus.  At  the  anterior  jiortion  of  the  pinna, 
near  the  first  curve  of  the  helix,  there  is  a  projection, — the  spina  helicis, — and 
behind  it  is  a  sliort  cleft — the  fissure  of  the  helix.  Bands  of  fibrous  tissue — the 
so-calk'd  ligaments  of  the  pinna — connect  this  structure  with  the-  cranium,  and 
otiiors  unite  the  vavinus  jiarts  of  the  cartilage.  Anteriorly  a.  band  of  tibrous 
tissue  connects  the  spina  helicis  with  the  root  of  the  zygoma,  and  fibrous  tissue 
attac'lies  the  concha  to  the  mastoid  process  posteriorly. 

Tlic  intrinsic  muscles  of  the  auricle  are  small,  rudimentary,  nnd  uin'mpor- 
l:iiit.     'I'hc  cxli'iiisic  nmscles  have  Ihhmi  described  with  the  fiice. 

I!i.n(ii>  Sri'i'LY. — The  arteries,  wilh  wliich  the  pinna  is  avcU  su]i]ilied,  are 
ili-rivcd  friiiii  llii'  posterior  auricular,  occipital,  and  .superficial  tem])oral  arteries. 
They  are  accompanied  by  c'orresponding  veins. 


PLATE  XCIX. 


Helix 


Darwin's  tubercle 


Helicis  major  m. 


Tragicus  m. 
Fibrous  band 
is  minor  m. 


Obliquus  auris  m 


Tpansversus  auris  m. 


Fissure  of  Santorini 


Antitragicus  m. 
Processus  caudatus 


S—  11—26 


INTRINSIC  MUSCLES  OF  PINNA. 
401 


THE   ORGAN  OF  HEARING.  403 

Nerve  Supply. — The  scnsofv  iutvcs  of  tlio  j)inna  ;uv  devivud  i-l:ii'tly  iVoni 
tlie  auriculo-temporal  and  auiiculaiis  magiius,  altliough  filaments  are  coiitriliutrd 
by  the  occipitalis  niiiu>r  ami  tlie  auricular  branch  of  the  vagus  nerve;  the  motor 
nerves  to  the  muscles  of  tiie  auricle  arc  derived  from  the  facial  nerve.  As  the 
back  of  the  pinna  is  suiiplied  by  the  auricularis  magnus  and  small  occipital 
nerves  and  the  lobule  by  the  auricularis  magnus  nerve,  pain  in  the  pinna  may  be 
caused  by  irritation  of  the  cervical  nerves  in  caries  of  the  cervical  vertebne  or  by 
enlarged  cervical  lymphatic  glands. 

The  lymphatics  of  the  pinna  are  numerous,  and  pass  to  the  preauricular 
or  superficial  parotid  lymphatic  glands  and  to  the  posterior  auricular  lymphatic 
glands. 

The  External  Auditory  Canal  is  a  slightly  curved  passage,  convex  upward, 
which  leads  inward  and  a  little  forward  for  a  distance  of  about  twenty-four  milli- 
meters, or  one  inch,  to  the  membrana  tympani.  The  highest  portion  of  the 
canal  is  about  at  its  middle.  Drawing  the  pinna  upward  and  backwai'd  has  a 
tendency  to  straighten  the  canal ;  this  is  done  prior  to  inspection  of  the  canal  or 
to  introduction  of  instruments.  Owing  to  the  obliquity  of  the  tympanic  mem- 
brane, the  anterior  and  inferior  walls  of  the  external  auditory  meatus  are  the 
longer,  and  the  internal  extremity  of  the  canal  is  wedge-shaped,  terminating  in  a 
narrow  recess — the  sinus  of  the  external  auditor}'  meatus.  Small  foreign  bodies 
which  have  lodged  in  the  sinus  of  the  canal  must  be  removed  carefully,  as  the 
instruments  must  approach  the  membrana  tympani  closeh'.  The  meatus  is  elliptic 
at  the  external  orifice,  the  vertical  diameter  of  the  canal  being  the  greater ;  near 
the  mefnbrana  tympani  the  transverse  diameter  is  the  greater.  Although  the 
orifice  of  the  external  meatus  is  elliptic,  ear  specula  which  are  round  are  more 
desirable  than  the  elliptic  instruments,  for  they  can  be  rotated  while  being 
introduced.  The  outer  one-third  of  the  wall  of  the  external  auditory  meatus  is 
cartilaginous  and  continuous  with  the  cartilage  of  the  pinna  ;  this  portion  is  about 
eight  millimeters,  or  three-eighths  of  an  inch,  in  length,  and  the  cartilage  presents 
one  or  two  fissures,  known  as  the  incisure  Santorini,  wliich  are  filled  with  fibrous 
tissue.  The  inner  or  osseous  portion  is  somewhat  longer,  and  measures  less  in 
diameter  than  the  cartilaginous  portion,  its  average  length  being  about  sixteen 
millimeters,  or  five-eighths  of  an  inch.  At  birth  the  osseous  portion  is  represented 
merely  by  an  incomplete  bony  ring, — the  annulus  tympanicus, — and  a  mass  of 
epithelial  cells  and  cerumen  fills  the  canal. 

The  Integument  lining  the  meatus  is  thin,  and  firmlj'  attached  to  the  under- 
lying parts ;  consequently  inflammatory  processes,  such  as  furuncles,  are  accom- 
panied by  considerable  pain ;  the  cutaneous  lining  is  continued  OA-er  the  tympanic 
membrane    as   a    delicate    covering,    forming   the    outer   layer   of  that  structure. 


404  SURGICAL  ANATOMY. 

Hairs  and  sebaceous  glands  are  found  in  the  cartilaginous  portion  of  the  meatus, 
as  M'ell  as  slightly  modified  sweat  glands  whiclr  secrete  the  cerumen,  or  ear  wax. 
When  the  cerumen,  or  wax,  is  secreted  too  rapidlj^  the  meatus  becomes  occluded, 
and  deafness  and  tinnitus  aurium  result.  No  hairs  or  glands  are  found  in 
the  osseous  portion  of  the  external  auditory  meatus. 

In  otitis  externa  the  skin  of  the  external  auditory  meatus  is  inflamed,  and 
there  may  be  a  purulent  discharge  from  that  canal. 

Occlusion  of  the  external  auditory  meatus  may  occur  as  a  congenital  defect 
or  from  the  presence  of  polypoid  growtlis  arising  from  granulations  projecting 
through  a  perforation  in  the  membrana  tympani  in  chronic  otitis  media,  from 
exostoses  from  the  bony  wall,  from  foreign  bodies,  or  from  an  excessive  quantity 
of  cerumen. 

Foreign  bodies  may  remain  in  the  external  auditory  meatus  for  many  years 
without  causing  injury  or  inconvenience,  and  they  may  not  be  discovered  until 
otoscopic  examination  for  some  condition  in  no  way  connected  with  the  presence  of 
the  foreign  body.  Unskilful  attempts  at  removal  have  inflicted  nearly  all  the 
injury  following  the  presence  of  these  foreign  bodies.  No  attempt  should  be  made 
to  remove  a  foreign  body  until  it  is  seen  in  the  meatus.  Insects  or  other  foreign 
bodies  may  be  removed  by  syringing  gently  with  a  slender  stream  of  warm  water. 
If  this  fail,  a  small  hook,  which  can  be  made  of  a  hair-pin,  should  be  inserted 
and  kept  in  view,  the  canal  being  well  illuminated.  If  the  walls  of  the  canal 
are  swollen,  removal  of  the  foreign  body  should  be  deferred  until  the  swelling  has 
subsided. 

Relations. — A  portion  of  the  parotid  gland  is  in  relation  with  the  lower 
and  anterior  wall  of  the  •external  auditory  meatus ;  this  explains  how  parotid 
tumors  can  cause  narrowing  of  that  canal,  and  how  abscesses  of  the  parotid  gland 
might  open  into  it,  the  fissures  in  the  cartilage  affording  a  favorable  situation  for 
perforation.  The  anterior  wall  of  tlie  meatus  is  also  in  relation  with  the 
condyle  of  the  lower  jaw,  so  that  firm  closure  of  the  mouth  has  a  tendency  to 
narrow  the  lumen  of  the  meatus.  "When  the  condyle  is  driven  forcibly  back- 
ward, as  by  a  blow  or  a  fall  on  the  chin,  tlie  bony  wall  of  the  meatus  may  be 
fractured.  The  posterior  and  upper  walls  of  the  canal  are  formed  by  parts 
of  the  mastoid  and  of  the  scpiamous  portion  of  the  temporal  bone,  and  often 
only  a  thin,  osseous  partition  separates  it  from  the  mastoid  cells,  so  that  caries 
of  the  osseous  wall  of  the  external  auditory  meatus  may  be  followed  by  mastoid 
disease. 

Blood  Sui'it.v. — Tin-  blood  supply  of  the  external  auditory  meatus  is 
derived  from  liranches  of  the  internal  maxillary,  posterior  auricular,  and  super- 
ficial temp(ii-al  arteries. 


PLATE  C, 


Attic 


Tensor  tympani  m. 


Pinna 


Internal  carotid  a, 


Eustachian  tube 


External  auditory  meatus 


Internal  carotid  a. 
Membrana  tympani  Stapes 


EXTERNAL  AND  MIDDLE  EAR. 
405 


THE  ORGAN  OF  HEARING.  407 

The  niiis  arnnniiany  the  etinvspomUiig  arteries  ami  eiiipt}'  into  tlie  teiuiiural, 
internal  maxillary,  and  posterior  auricnlar  veins. 

Nkkvk  Srri'i.v. — The  nerve  .'^ujijily  of  the  external  auditory  meatus  is 
derived  tVom  hranehes  of  the  aurieulo-temporal,  the  avirieularis  niagnus,  and  the 
auricular  branch  of  the  vagus  nerve.  Interesting  reflex  disturbances  are  at  times 
caused  by  the  presence  of  foreign  bodies,  wax,  or  specvila  through  irritation 
retleeted  along  the  auricuhir  branch  of  the  imeumogastric  nerve  and  referred  to 
the  ]iarts  supplied  by  the  parent  trunk  ;  coughing,  faintness,  and  nausea  and 
vomiting  may  be  induced  in  tliis  manner.  Sneezing  is  also  produced  by  the  pres- 
ence of  foreign  bodies  or  specula  in  the  external  auditory  meatus.  The  irritation 
is  reflected  probably  along  the  aurieulo-temporal  nerve  to  the  Gasserian  ganglion 
or  other  centers  of  the ,  fifth  nerve,  and  tlience  referred  to  the  nose  through 
branches  of  the  superior  maxillary  nerve.  Cough  produced  by  irritation  reflected 
from  the  ear  is  termed  ear  cough.  Earache  associated  with  toothache  in  the 
upper  teeth  may  be  explained  in  tlie  same  manner.  Earache  frequently  is 
associated  with  toothache  in  the  lower  teeth  and  disease  of  the  tongue ;  the  pain  in 
the  ear  is  due  probably  to  irritation  reflected  along  the  inferior  dental  nerve  and 
lingual  nerve,  and  referred  to  the  ear  through  the  auriculo-temjioral,  the  other 
sensory  branch  of  the  inferior  maxillary  nerve. 

The  lymphatics  of  the  external  auditory  meatus  follow  the  veins,  and 
terminate  in  the  parotid  and  posterior  auricular  lymphatic  glands. 

DissECTiox. — The  tympanum  is  to  be  opened  with  a  chisel  l)y  the  removal  of 
its  bony  roof  (tegmen  tymj)ani)  ;  the  opening  is  made  to  the  outer  side  of  the 
elevation  produced  by  the  superior  semicircular  canal,  and  is  enlarged  carefully, 
uncovering  also  the  mastoid  antrum  and  the  internal  auditory  meatus. 


THE  MIDDLE  EAR. 

The  Middle  Ear,  or  Tympanum,  is  a  small,  irregular  air  chamber,  situated  in 
the  petrous  portion  of  the  temporal  bone,  and  lined  with  mucous  membrane ;  it  is 
interposed  between  the  external  auditory  meatus  and  the  internal  ear.  Its 
antero-posterior  lengtli  measures  about  twelve  millimeters,  or  onedialf  of  an  inch  ; 
its  widtli  is  from  two  millimeters  to  four  millimeters,  or  from  one-twelfth  to  one- 
sixth  of  an  inch,  and  it  is  narrowest  opposite  the  center  or  umbilicus  of  the 
tympani.c  membrane  which  is  opposite  the  promontory  ;  vertically  it  is  about 
thirteen  millimeters,  or  somewhat  more  th^n  half  an  inch,  in  dei^th ;  this  last 
measurement  includes  the  recessus  epitympanicus,  or  attic. 

The  attic,  or  recessus  epitympanicus,  is  the  highest  portion  of  the 
tympanic    cavity.     It    is   situated    above    the    level    of  the    membrana  tympani. 


408  SURGICAL  ANATOMY. 

and  contains  the  head  of  the  malleus  and  part  of  the  incus,  and  leads  into  the 
mastoid  antrum. 

The  roof  of  the  tympanum  consists  of  a  thin  j^late  of  bone — tegmen  tympani 
— which  separates  the  tympanum  from  the  cranial  cavity  ;  it  forms  part  of  the 
antero-superior  surface  of  the  jjetrous  portion  of  the  temporal  bone.  Destruction 
of  this  osseous  lamina  or  extension  through  it  of  the  inflammatory  process  in 
chronic  otitis  media  may  lead  to  meningeal  or  cerebral  complications,  such  as 
extradural  abscess,  meningitis,  abscess  of  the  temporo-sphenoid  lobe  of  the 
cerebrum,  and  cereliellar  abscess.  In  children  under  one  year  of  age  the  presence 
of  the  petro-squamosal  suture  in  the  tegmen  tympani  favors  this  complication. 

The  floor  is  formed  by  a  thin,  bony  plate  situated  between  the  tympanum 
and  the  jugular  fossa.  Destruction  of  tliis  plate  of  bone  by  caries  in  otitis  media 
may  cause  fatal  hemorrhage  or  septic  thrombosis  of  the  internal  jugular  vein, 
embolism,  and  metastatic  abscess. 

The  anterior  wall  is  cjuite  narrow,  and  is  deficient  superiorly,  inasmuch  as 
the  Eustachian  tube  opens  into  the  tympanum  in  this  situation  about  four  milli- 
meters, or  ftne-sixth  of  an  inch,  above  the  floor.  Just  above  the  entrance  of  the 
tube  is  the  opening  of  the  canal  which  lodges  the  tensor  tympani  muscle.  Owing 
to  the  position  of  the  tympanic  orifice  of  the  Eustachian  tube  above  the  level  of 
the  floor  of  tlie  tympanum,  fluid  which  has  entered  the  tympanum  by  way  of  the 
Eustachian  tube,  through  snuffling  water  in  surf-bathing  or  in  using  the  nasal 
douche,  can  not  all  escape  through  the  tube,  and  otitis  media  is  likely  to  result. 
Below  the  orifice  of  the  Eustachian  tube  the  anterior  wall  is  composed  of  a  thin, 
bony  lamina,  situated  between  the  tympanum  and  the  carotid  canal.  Caries  of  this 
thin  plate  of  bone  may  occur  in  otitis  media,  and  ulceration  into  the  internal 
carotid  artery  with  fatal  hemorrhage  may  follow. 

The  Eustachian  tube  is  fthe  anterior  extension  of  the  tympanic  cavity  Avhich 
connects  the  middle  ear  with  the  naso-pharynx  ;  it  passes  inward,  downward,  and 
forward  from  the  tympanum,  is  about  thirty-five  millimeters,  or  an  inch  and  a  half, 
in  length,  and  in  its  several  portions  varies  from  two  to  five  millimeters,  or  from 
one-twelfth  to  one-fifth  of  an  inch,  in  diameter.  It  consists  of  an  osseous  and 
a  cartilaginous  portion,  the  former  being  about  twelve  millimeters,  or  one-half 
of  ail  inch,  long,  and  the  latter  about  twenty-five  millimeters,  or  one  inch, 
long.  Tlie  cartilaginous  portion  is  somewhat  trumpet-shaped,  being  widest  at  the 
pharyvf/eal  orifice.  It  is  formed  by  a  cartilaginous  plate  which  is  triangular  in 
shajje  and  folded  ujion  itself,  thus  leaving  on  the  inferior  and  external  aspect  of 
the  tube  an  interval  which  is  filled  with  fibrous  tissue  (fascia  salpingo-pharyngea), 
ami  by  a  |iiirt  nf  the  tensor  jialati  muscle  called  the  dilator  tubie.  (See  also 
description   nf  jihaiynx.)      The   bony  portion,   which   is   smaller   than    the    carti- 


PLATE  CI. 


Suspensory  ligament  of  malleus 
Prussak 


Membra 


External  ligament  of  malleus 


gracilis 
tympani  tendon 


External  a 


g  process  of  incus 


meatus 


Processus  brevis 

Manubrium  of  malleus 

Cutaneous  layer' 
Mucous  layer 
Fibrous  layer' 


Eustachian  tube 


Canal  for  tensor 
tympani  m, 


Stapes 
Membrana  tympani 


ANTERIOR  VIEW  OF  RIGHT  TYMPANUM. 
409 


\ 


THE   OnOAy   OF  UFA  RING.  -411 

laginous  portimi  of  tlie  tube,  is  situated  at  the  junction  of  the  squamous  and 
petrous  portions  of  tlie  temporal  bone ;  the  isthmus  iubfc,  its  narrowest 
portion,  is  situah'd  at  the  junrtiuu  of  the  bony  and  i'artilai;in(ais  parts.  Tlie 
Eustachian  tube  is  lined  with  mucous  nicndirane  which  is  continuous  with  that  of 
the  naso-pharynx  and  tliat  lininj;-  tlie  middle  ear.  Conseqviently  inflammatory 
l)roccsscs  of  the  naso-i)haryn.\,  by  direct  continuity  of  the  tissues,  may  lead  to 
involvement  of  the  middle  ear.  The  tympanic  orifice  of  the  Eustachian  tube  is 
situated  in  the  anterior  wall  of  the  tympanum,  about  four  millimeters  above  the 
floor  of  that  cavity,  and  the  pharyngeal  orifice  is  in  the  lateral  wall  of  the  naso- 
pharynx, beliind  the  posterior  naris,  at  the  level  of  the  posterior  extremity  of  the 
inferior  turbinated  bone.  Normally  the  canal  is  closed,  except  during  swallowing, 
when  it  is  opened  by  the  tensor  palati  muscle,  levator  palati  muscle,  and  the 
salpingo-pharyngeus,  which  is  the  portion  of  the  palato-pharyngeus  muscle 
attached  to  the  Eustachian  tube.  The  action  of  these  muscles  during  swallowing 
affords  an  opportunity  to  inflate  the  middle  ear  by  way  of  the  nose,  naso-pharynx, 
and  Eustachian  tube. 

In  Politzer's  method  of  inflation  of  the  middle  ear  the  patient  takes  some 
water  in  his  mouth  ;  the  nozle  of  a  caoutchouc  bag  which  contains  air  is  inserted 
into  one  nostril ;  the  nostrils  are  closed  with  the  fingers  of  one  hand  ;  and  as  the 
patient  swallows  the  water  the  bag  is  suddenly  and  forcibly  compressed  with  the 
other  hand.  In  the  method  of  Valsalva  the  patient  closes  the  mouth  and  nose 
firmly  and  pufls  out  the  cheeks  liy  a  forcible  effort  at  expiration.  Air  is  driven 
through  the  Eustachian  tube,  and  a  sense  of  pressure  and  fullness  is  felt  in  the 
middle  ear.  This  method  is  not  altogether  safe,  on  account  of  the  increased  ten- 
sion produced  in  the  blood-vessels  and  the  danger  of  hemorrhages  and  apoplexy. 
The  middle  ear  may  also  be  inflated  by  the  caoutchouc  bag  and  Eustachian 
catheter;  tlie  metlioil  for  introducing  the  catheter  is  described  with  the  pharynx. 

The  Eustachian  tube  may  be  closed  by  the  extension  of  hypertrophic  nasal 
and  naso-pharyngeal  catarrh  into  the  tube,  or  the  pharyngeal  orifice  of  the 
tube  may  be  obstructed  mechanically  by  growths  of  the  nose  or  naso-pharynx. 
Occlusion  of  this  tube  causes  autophony,  or  loud  but  muffled  sound  of  the 
individual's  voice,  tinnitus  aurium,  or  false  sounds  in  the  ears,  a  sensation  of  ten- 
sion or  distention  in  the  ears,  and  more  or  less  deafness. 

In  the  mucous  membrane  of  the  Eustachian  tube  and  near  the  pharyngeal 
end  of  the  tube  there  are  a  few  mucous  glands  and  a  quantity  of  lymphoid  tissue ; 
this  latter  is  sometimes  referred  to  as  the  tubal  tonsil. 

Relations. — On  the  outer  side  of  the  Eustachian  tube  are  the  tensor  palati 
and  levator  palati  nniscles,  the  otic  ganglion,  the  inferior  maxillary  nerve,  and  the 
middle  meningeal  artery  ;  on  the  inner  side  is  the  wall  of  the  phar^^nx. 


412  SURGICAL  ANATOMY. 

Blood  Supply. — The  blood  supjjly  of  the  Eustachian  tube  is  derived  from 
the  ascending  pharyngeal,  middle  meningeal,  and  Vidian  arteries. 

Nerve  Supply. — The  nerve  sujiply  of  the  Eustachian  tube  is  derived  from 
the  Vidian  nerve  and  the  tympanic  plexus. 

The  posterior  wall  of  the  middle  ear  presents  at  its  upper  portion  a  large 
opening  which  leads  into  the  mastoid  antrum  ;  through  this  opening  the  mucous 
membrane  is  continuous  from  one  cavity  to  the  other,  so  that  inflammation  in  the 
middle  ear  may  lead  to  involvement  of  the  mastoid  air  cells.  Below  the  ojiening 
into  the  antrum,  near  the  inner  wall  of  the  tympanum  and  posterior  to  the 
fenestra  ovalis,  is  a  hollow,  cone-shaped  projection  known  as  the  pyramid,  at  the 
summit  of  which  there  is  a  perforation  for  the  passage  of  the  tendon  of  the 
stapedius  muscle.  External  to  the  pyramid  is  the  iter  ckordas  posterius,  through 
which  the  chorda  tympani  nerve  passes. 

As  the  Mastoid  Antrum  and  Mastoid  Cells  communicate  with  the  middle 
ear,  they  are  cavities  accessory  to  the  tympanic  cavity. 

The  mastoid  portion  of  the  temporal  bone  contains  numerous  spaces,  some 
of  which  are  filled  with  air  ;  these  communicate  with  the  middle  ear,  and  are 
called  mastoid  cells  ;  other  spaces  which  occupy  the  tip  of  the  process  are  filled 
with  marrow.  Of  the  air  cavities,  the  mastoid  antrum  is  the  largest  and  most 
important.     Leidy  described  the  mastoid  antrum  as  a  part  of  the  tympanum. 

The  Mastoid  Antrum  is  an  air  cavity  of  variable  size,  usually  about  that  of  a 
large  pea,  or  from  four  to  six  millimeters  in  diameter,  and  is  situated  posterior  to 
the  tympanum,  about  on  a  level  with  the  highest  part  of  that  cavit^^  It  is  lined 
with  mucous  membrane  or  muco-periosteum,  which  is  directlj'  continuous  with 
that  of  the  attic  of  the  tympanum  and  mastoid  cells.  The  mastoid  antrum  is 
present  at  birth. 

The  roof  of  the  mastoid  antrum  (tegmcn  antri)  is  a  thin  plate  of  bone  about 
one  millimeter  in  thickness,  situated  external  to  the  eminence  produced  by  the 
superior  semicircular  canal ;  it  separates  the  mastoid  antrum  from  the  cranial 
cavity,  and  is  perforated  by  minute  veins  which  empty  into  the  superior  petrosal 
sinus ;  at  times  the  tegmen  is  distinctly  cribriform,  and  it  may  be  partly  or  wholly 
absorbed  in  old  age. 

The  floor  of  the  antrum,  which  is  not  infrequently  on  a  lower  level  than  the 
communication  between  the  tympanum  an<l  antrum,  is  formed  by  the  substance 
of  the  mastoid  portion  of  the  temporal  bone,  and  usually  contains  the  orifices  of 
some  of  the  other  mastoid  cells. 

The  anterior  wall  of  the  antrum  is  Ihin,  and  may  be  perforated  ;  it  separates 
the  mastoid  anti-um  from  the  bony  part  of  the  external  auditory  meatus.  Inflam- 
matory processes  may  extend  from  the  mastoid  antrum  through  this  wall  to  the 


PLATE  Cll. 


Suspensory  ligament 
of  malleus 

Head  of  nnalleus 


Roof  of  tympanic  cavity 


Mastoid  antrum 


Mastoid  cells 
Anterior  portion  of  membrana  tympani 
Anterior  wall  of  external  auditory  meatus  chiseled  to  a  deeper  plane 


MEMBRANA  TYMPANI  AND  ITS  INCLINATION. 
413 


THE   ORGAN  OF  HEARING.  415 

external  auditorv  meatus,  m-  vice  versa.  Tlirough  tliis  wall  a  lua.stuid  aliseess  may 
be  evaeviated  liv  way  of  tlir  cxtci-ual  auditory  uieatus. 

The  posterior  wall  of  the  antrum  is  a  lH)uy  lamina  of  variable  thickness, 
separating  the  antrum  from  the  groove  for  the  sigmoid  sinus;  through  it  small 
veins  pass  from  the  middle  ear  and  mastoid  antrum  to  the  sigmoid  sinus.  By  way 
of  these  veins  septic  material  due  to  otitis  media  or  mastoid  disease  may  reach  the 
sigmoid  jwrtion  of  the  lateral  sinus,  and  cause  septic  thrombosis  and  embolism. 

The  inner  wall  of  the  mastoid  antrum  is  from  nine-sixteenths  to  tin-ee-fourlhs 
of  an  inch,  or  fourteen  to  eighteen  millimeters,  distant  from  the  base  line  of  the 
supra-meatal  triangle  (MacEwen).  The  facial  ciinal  lies  in  the  inner  wall  of  the 
passage  from  the  mastoid  antrum  to  the  tympanum.  Tins  canal,  which  is 
separated  from  the  tympanum  by  a  thin,  osseous  lamina,  is  situated  above  the 
oval  window  of  the  tympanum  ;  on  the  inner  side  of  the  antro-tympanal  passage- 
way tlie  canal  curves  and  then  descends  to  the  stylo-niastoid  foramen.  The  wall 
of  the  canal  is  thin  in  children,  and  maj^  be  defective  in  that  portion  which 
lies  over  the  oval  window  ;  the  nerve  is  therefore  more  likely  to  suffer  from 
neuritis  in  otitis  media  in  children  than  froip  the  same  disease  in  adults. 

The  outer  wall  of  the  mastoid  antrum  is  formed  by  the  descending  plate  of 
the  scpiamous  portion  of  the  temporal  bone  ;  the  antrum  is  from  one-half  to  three- 
fifths  of  an  inch,  or  from  twelve  to  fifteen  millimeters,  distant  from  the  surface  of 
the  bone.  In  an  infant  the  outer  wall  of  the  mastoid  antrum  is  about  two  milli- 
meters in  thickness,  and  in  a  child  nine  years  of  age  it  is  ten  millimeters  thick 
(Symington).  In  tlie  second  year  this  wall  rapidly  increases  in  thickness.  In 
infants  the  descending  plate  of  the  squamosal  bone  is  separated  from  the  mastoid 
process  by  a  suture,  the  masto-squamosal  suture.  In  adults  this  suture  at  times 
persists  wliolly  or  partially.  In  children,  on  account  of  the  tenuity  of  the  external 
wall  of  the  mastoid  antrum  and  the  presence  of  this  suture,  pus  may  find  its  way 
to  the  exterior  through  the  middle  ear  and  mastoid  antrum,  and  form  a  subperios- 
teal abscess  over  the  mastoid  portion  of  the  temporal  bone.  In  some  cases  this 
wall  has  been  perforated  spontaneously  by  absorption  of  the  bone.  In  these  cases 
an  air  tumor,  or  pneumatocele,  which  can  be  inflated  through  the  Eustacliian  tube 
may  form  over  the  mastoid  process. 

Tlie  Supra-meatal  Triangle  of  MacEwen  is  bounded  above  by  the  posterior 
root  of  the  zygoma,  which  runs  nearly  horizontally  backward  ;  the  antero-inferior 
boundary  is  formed  hx  the  posterior  and  upper  margin  of  the  bony  meatus ;  the 
posterior  boundary  is  formed  by  a  perpendicular  line  extending  from  the  most 
posterior  portion  of  the  bony  meatus  to  tlie  posterior  root  of  tlie  zygoma.  The 
apex  of  this  triangular  area  is  directed  forward,  and  the  area  itself  is  usually 
somewhat  depressed.     Through  this  triangle  the  mastoid  antrum  may  be  reached 


416  SURGICAL  ANATOMY. 

with  safety,  if  the  perforation  be  directed  inward  and  somewhat  upward  and 
forward,  or  parallel  with  the  external  auditory  meatus.  If  the  mastoid  process 
is  opened  behind  this  triangle,  the  knee  of  the  sigmoid  portion  of  the  lateral 
sinus  is  in  danger  of  being  injured,  particularly  if  the  perforation  be  made 
directly  inward,  as  that  sinus  is  only  from  three  to  six  millimeters  from  the 
posterior  extremity  of  the  mastoid  antrum.  The  posterior  root  of  the  zygoma  indi- 
cates the  level  of  the  floor  of  the  cranial  cavity  ;  should  tiie  operator  pierce  the 
bone  above  this  line,  the  ci'anial  cavity  is  likely  to  be  opened.  As  previously 
stated,  the  mastoid  antrum  in  the  adult  is  usually  from  one-half  to  three-fifths 
of  an  inch,  or  from  twelve  to  fifteen  millimeters,  from  the  surface  of  the  bone ;  for 
this  reason  the  chisel  or  gimlet  should  enter  the  mastoid  antrum  at  a  depth  not 
greater  than  fifteen  millimeters.  As  tlie  result  of  long-standing  disease,  the  bone 
over  the  mastoid  antrum  may  be  thickened  and  sclerosed.  If  the  inner  wall  of  the 
antrum  is  encroached  upon,  the  facial  nerve  may  be  injured  by  the  chisel  or  other 
instruments  used  by  the  operator. 

Tlie  Mastoid  Cells  vary  exceedingly  as  to  number  and  size.  They  are  absent 
at  birth,  and  prior  to  puberty  they  are  few  in  number.  They  attain  their  full 
development  in  the  young  adult,  and  occup}'  the  greater  portion  of  the  mastoid 
process,  opening  directly  or  indirectly  into  the  mastoid  antrum.  They  are 
lined  with  muco-periosteum  which  is  continuous  with  that  of  the  mastoid  antrum. 
Posteriorly  they  cease  abruptly  at  the  occipito-temporal  suture.  They  are  sepa- 
rated from  the  sigmoid  portion  of  the  lateral  sinus  by  a  thin  plate  of  bone,  through 
which  veins  pa,ss  from  these  cells  to  the  sinus,  affording  a  ready  means  of  infection 
and  of  production  of  septic  throml)osis  of  the  sinus. 

The  Outer  "Wall  of  the  Middle  Ear  is  formed  l:)y  the  membrana  tympani  and, 
to  a  slight  extent,  hy  bone. 

The  membrana  tympani  is  an  elliptic  or,  at  times,  oval  membranous  disc, 
attached  to  a  grooved  ridge  of  bone  at  the  bottom  of  the  external  auditory  meatus. 
Its  greatest  diameter,  measured  from  its  posterior  and  upper  portion  forward  and 
downward,  is  ten  millimeters  in  lengtli ;  the  vertical  measurement  is  slightly  less  ; 
it  is  one-tenth  of  a  millimi^ter  in  thit'kness.  Tlie  mcmljrane  is  situated  obliquely, 
its  outer  surface  being  directed  outward,  downward,'  and  forward.  It  is  directed 
downward  and  outward  at  an  angle  of  about  forty-five  degrees,  and  forward  and 
outward  at  an  angle  of  about  ten  degrees.  In  the  infant,  at  birth,  this  oblitjuity  is 
greater  and  the  membrane  is  almost  horizontal.  Its  outer  surface  is  concave,  the 
center  being  the  deepest  point  of  the  concavity,  for  the  extremity  of  the  handle 
of  tbc  malleus  is  bci-c  attached,  and,  as  it  were,  draws  the  membrane  inward. 
The  depressed  center  is  known  as  the  timho.  The  bony  ring  to  which  the 
tympanic    membrane  is  attached  is  incomjilete  above,  leaving  a  notch  {notch  of 


S—  11— 27 


PLATE 


Short  process  of  malleus 


Anterior  fold  of  membrana  tympan 


.<^ 


^■b 


A 


Shraphell's  membrane 

Posterior  fold  of  membrana  tympani 
Long  process  of  incus 


Cone  of  light 
Anterior  portion  of  membrana  tympani 


Posterior  portion  of  membrana 
tympani 


EXTERNAL  VIEW  OF  MEMBRANA  TYMPANI  OF  LEFT  EAR. 
418 


THE   ORGAX   OF  HKAniXn.  419 

Tiifini),  which  is  hlicd  in  ]>y  a  tliiiinor  ami  Inoscr  j^irtion  of  tiic  niciiiliraiif, 
known  as  the  mciithnina  Jlaccidn,  or  Shrapncll's  nwiiibranc.  Tiic  UK'nilirana 
tynqiani  consists  of  three  layers:  an  outer  cuticular  covering-:  a  niiildlc,  iitirons 
h\yer ;  and  an  inner,  mucous  lining. 

Inspection. — When  vicwnl  through  a  speculum  during;  lite,  the  mcndirana 
tympani  is  of  a  jn'arly  ,t;i'ay  color,  and  a]i}iears  smooth  and  jiolishech  I'Lvtendiui;- 
downward  and  backward  with  its  ai)ex  at  the  umbo  is  a  co)ie  of  lii/hl,  which  is  of 
value  in  the  diagnosis  of  disea.se  of  the  tympanum  and  memhrana  tympani. 
The  handle  of  the  malleus  and  its  short  process,  and,  posterior  to  the  handle  of 
the  malleus,  the  long  process  of  the  incus,  can  frequently  be  seen  through  the 
membrane.  From  the  short  jirocess  of  the  malleus  two  folds  extend  to  the 
margins  of  the  notch  of  Ilivini  ;  these  are  known  as  the  (niterior  and  t\ie  jDostcrior 
fold  of  the  membrane,  and  between  them  is  the  membrana  flaccida,  so  named  on 
account  of  its  laxity.  Owing  to  this  laxity  perforations  of  the  membrana  flaccida 
give  rise  to  but  slight  loss  of  hearing.  The  remainder  and  major  portion  of  the 
drum  is  known  as  the  mevibmna  tensa. 

Perforation  or  rupture  of  the  membrana  tympani  is  frecjuently  produced  by 
traumatism,  as  by  slender  foreign  bodies  accidentally  pushed  far  into  tlie  external 
auditory  canal,  or  by  the  escape  of  jnis  in  otitis  media.  Perforation  of  the  mem- 
brana flaccida  occurs  more  commonly  when  the  disease  is  confined  to  the  attic ; 
perforation  of  the  posterior  portion,  when  the  disease  is  confined  to  the  mastoid 
antrum ;  and  perforation  of  the  lower  portion  of  the  membrana  tensa  is  most 
frequent  on  account  of  its  low  position.  Owing  to  the  inela,sticity  of  the  mem- 
brane, perforations  do  not  gape  much.  Traumatic  perforations  heal  readily, 
whereas  tho.se  associated  with  suppurative  otitis  media  seldom  close.  Granulation 
tissue  from  the  inflamed  mucous  membrane  of  the  tympanum  projecting  through 
the  perforation  forms  polypoid  growths  which  conceal  the  opening,  and  sometimes 
hide  the  tympanic  membrane.  These  growths  are  associated  with  copious  sup- 
jiuration. 

Paracentesis  of  the  tympanum,  or  puncture  of  the  tympanic  membrane,  is 
frequently  practised  by  the  surgeon  to  relieve  tension  and  allow  of  the  discharge 
of  inis. 

The  point  selected  is  in  the  lower  or  subundiilical  portion  of  the  mend)rane,  or 
wherever  the  bulging  is  greatest.  Paracentesis  of  the  upper  portion  of  the  mem- 
brane is  attended  by  danger  of  injuring  the  malleus,  incus,  or  chorda  tympani 
nerve,  and  jiaracentesis  of  the  lower  portion  of  the  membrane  must  be  cautiously 
performed,  for  the  inner  wall  of  the  tympanum  is  situated  only  from  two  milli- 
meters to  four  millimeters,  or  from  one-twelfth  to  one-sixth  of  an  inch,  internal 
to  the  tympanic  membrane. 


420  SURGICAL  ANATOMY. 

After  the  membrana  tympani  has  been  destroyed  by  ulceration  and  the 
malleus  and  incus  have  escaped  with  the  pus,  a  plug  of  cotton  inserted  into  the 
tympanum  against  the  stapes  will  serve  as  an  artificial  membrana  tympani. 

Blood  Supply. — The  blood  supply  of  the  membrana  tympani  is  derived 
mainly  from  the  tymjaanic  branches  of  the  internal  maxillary  ami  internal  carotid 
arteries. 

Nerve  Supply. — The  chief  nerve  supplying  the  external  surface  of  the 
membrana  tympani  is  the  auriculo-temporal.  According  to  Sappey,  Arnold's 
nerve  (the  auricular  laranch  of  the  vagus)  supplies  the  lower  portion  of  this 
surface  of  the  membrane,  and  branches  from  the  tympanic  plexus  supply  the 
inner  surface.     The  membrane  is  quite  sensitive. 

The  inner  wall  of  the  tympanum  presents  several  points  for  examination. 
A  conspicuous  rounded  elevation,  the  promontory  produced  by  part  of  the  first 
turn  of  the  cochlea,  is  seen ;  on  it  are  faintly  marked  grooves  for  the  tympanic 
plexus  of  nerves.  Above  the  posterior  portion  of  the  promontory  is  a  transverse 
oval  foramen, — the  fenestra  oralis,  or  oval  window, — which  leads  into  the  vestibule, 
and  when  the  ear  ossicles  are  in  situ,  is  closed  by  the  base  of  the  stapes.  Behind, 
it  is  the  pyramid,  at  the  summit  of  which  is  an  opening  for  the  tendon  of  the 
stapedius  muscle.  Below  the  promontory  is  ihe  fenestra  rotunda,  or  round  window, 
an  opening  which  leads  into  the  scala  tympani  of  the  cochlea,  and  in  the  recent 
state  is  closed  by  the  membrana  tympani  secundaria.  At  the  junction  of  the  inner 
wall  and  roof  of  the  tympanum,  above  the  oval  window,  is  a  rounded  ridge  of 
bone  passing  antero-posteriorly  ;  this  is  produced  by  the  fecial  canal  or  aque- 
ductus  Fallopii,  which  lodges  the  facial  nerve.  The  bony  lamina  separating  this 
nerve  from  the  cavity  of  the  middle  ear  is  quite  thin,  especially  in  children,  and 
in  otitis  media  tlae  facial  nerve  may  become  affected  by  neuritis,  leading  to 
paralysis  of  the  muscles  of  expression  upon  the  corresponding  side  of  the  face. 

The  mucous  membrane  of  the  tympanum  lines  the  tympanic  cavity,  and  is 
continuous  with  the  mucous  membrane  of  the  Eustachian  tube  and  with  that  of  the 
mastoid  antrum.  It  forms  the  inner  layer  of  the  tympanic  membrane,  and  is 
reflected  over  the  ossicles,  the  tendons  which  enter  the  tympanic  cavity,  and  the 
nerves  of  tlie  middle  ear. 

Middle  ear  disease  m;iy  lie  folldwed  liy  various  complications,  tlie  most  com- 
mon of  whicli  is  inflanunation  of  the  mastoid  .-inlrum  and  mastoid  air  cells,  result- 
ing in  mastoid  abscess.  As  tlu'  mucous  membrane  of  the  middle  ear  is  directly 
continuous  with  that  of  the  mastoid  antrum,  it  will  readily  be  seen  how  the 
inflammatory  process  maj'  extend  from  the  nose  to  the  naso-i)harynx.  Eustachian 
tulie,  tym])annm,  mastoid  antrum,  and  inastoid  cells. 

Througli    carious  destruction    of    the    tegnien    antri    or   tegmen  tympani  or 


PLATE  CIV. 


Head  of  malleus 


Tecmen  tym 


Suspensory  ligament  cf  inalleus 
,Chorda  tympani  n. 
nous 


Posterior  ligament  of  incus 


Orifice  of  Eustachian  tube 

Tensor  tympani  m 
Internal  surface  of  membrana  tympani 

Handle  of  malleus 


INTERNAL  VIEW  OE  RIGHT  TYMPANUM, 
42-2 


THE   nil(!A.\   OF  UKAUIXi}.  423 

tlinniii'li  tlu'  ]n'ri\':isciil:ii-  1\  nipliatics  ami  the  vi'in.><  wliicli  pierce  tlie  tegmen, 
extradural  abscess,  meningitis,  thrombosis  of  the  superior  petrosal  sinus,  and 
cerebral  and  cerebellar  abscess  nuiy  loult  from  otitic;  media  and  inastoid  disease. 
Thrombosis  of  the  sigmoid  sinus  and  i(iuse(|iiiid  septie  embolism  may  occur  by 
extcnsicm  ut' the  inliaiunuitinii  alniio-  the  veins  IVdni  the  mastoid  antrum,  mastoid 
cells,  and  tympannni  whieh  cuiiily  intu  the  sii;iiHiid  sinus. 

Ill  otitis  media  the  pus  usually  escapes  by  perforation  of  the  niembrana 
tympani,  and  may  pass  out  through  the  Eustachian  tube  into  the  pharynx,  or 
through  the  canal  for  the  tensor  tymjiani  muscle.  In  mastoid  disease  the  pus 
usually  escapes  through  the  tympanum  and  membrana  tympani,  and  may,  after 
destruction  of  the  comjiact  bone  on  tlie  intracranial  surface  of  the  mastoid  process, 
enter  the  I'ranial  cavity  and  form  an  extradural  abscess  ;  or  it  may  enter  the  neck 
over  or  under  the  prevertebral  fascia,  point  on  the  extei'ual  surface  of  the  mastoid 
process,  or  est-ijie  directly  into  the  external  auditory  meatus. 

The  Auditory  Ossicles  consist  of  the  malleus,  the  incus,  and  the  stapes, 
whii-h  form  a  chain  of  three  small  bones  that  transmit  the  impulses  of  sound 
waves  from  the  membrana  tympani  ti>  the  perilymph  and  endolymph  of  the 
internal  vay.  The  ossicles  and  the  ligaments  and  teutlons  attached  to  them  are 
covered  by  the  mucous  mend>rane  of  the  tympanum.  ~ 

The  malleus,  or  hammer,  consists  of  a  head,  a  neck,  a  handle,  or  manu- 
brium, the  iirocessus  lirevis,  and  the  processus  gracilis.  The  rounded  Itead  is 
situated  in  the  attic,  the  highest  portion  of  the  tympanic  cavity,  and  above 
the  level  of  tlie  membrana  tympani  ;  it  is  connected  with  the  roof  of  the  cavity 
by  fibrous  ti.ssuo  which  forms  the  so-called  svprrior  ligament  uf  the  malleus.  On  the 
posterior  aspect  of  the  head  of  the  malleus  is  a  cartilage-covered  surface  which 
articulates  with  the  body  of  the  incus.  Below  the  head  of  the  malleus  is  the  neck. 
The  manubrium,  or  handle,  is  connected  with  the  fibrous  layer  of  the  tymjianic 
membrane,  and  is  situated  between  this  layer  and  the  mucous  lining.  The 
processus  hreris  is  a  small  prominence  below  the  neck,  and  gives  attachment  to  the 
tensor  tyiii])ani  muscle.  The  processus  gracilis  is  a  long  and  slender  process  which 
passes  forward  to  the  Glaserian  fi.ssure.  In  the  adult  it  is  often  largely  represented 
by  fibrous  tissue. 

The  incus,  or  anvil,  resembles  in  shape  a  bicuspid  tooth  witli  diverging 
fangs ;  it  consists  of  a  body  and  two  pi'ocesses.  The  body  presents  a  concavo- 
convex  articular  surface  for  the  head  of  the  malleus ;  the  joint  between  these 
bones  is  surrounded  by  a  capsular  ligament  and  lined  by  a  synovial  mendirane. 
Tlie  sJwrf  process  pas.ses  backward,  and  is  connected  to  the  posterior  wall  of  the 
tym])anum  by  fibrous  tissue.  Tlie  loitg  process  descends  almost  jxarallel  witli  the 
manubrium  of  the  malleus,  but  posterior  and  internal   to  it.     It  terminates  in  a 


424  SURGICAL   ANATOMY. 

small,  knobbed  projection,  the  so-called  o.s  orbiculare,  which  articulates  wiUi  the 
head  of  the  stapes. 

The  stapes,  or  stirrup,  consists  of  a  head,  a  neck,  two  crura  ur  branches, 
and  a  foot-piece  or  base.  The  head  articulates  with  the  os  orbiculare  of  the  incus. 
This  joint  has  a  capsular  ligament,  and  is  lined  by  a  synovial  membrane.  The 
two  crura  diverge  as  they  leave  the  neck,  are  grooved  on  their  concave  sides,  and 
are  attached  to  the  foot-jnece  or  base,  M'hich  fits  into  the  oval  window.  The  base 
of  the  stapes  is  united  to  the  margin  of  that  opening  by  fibrous  tissue. 

In  otitis  media  the  ligaments  associated  with  the  ossicles  become  indurated 
and  stiffened  ;  through  loss  of  mobility  the  chain  of  bones  can  not  transmit 
imjiulses  to  the  internal  ear,  and  deafness  supervenes.  In  such  cases  hearing 
may  be  improved  liy  removal  of  the  jierforated  membrana  tympani,  the  malleus 
and  incus,  or  by  massage  administered  by  means  of  sound.  Caries  of  the  malleus 
and  incus  not  infrequently  occurs  in  otitis  media,  and  they  are  occasionally  dis- 
cliarged  with  the  pus  in  that  disease. 

The  Ligaments  situated  in  the  tympanum  are  associated  with  the  ossicles. 
They  consist  of  the  .superior,  the  anterior,  the  external,  and  the  internal  ligaments 
of  the  malleus,  the  ligament  of  the  incus,  and  the  capsular  ligaments. 

The  superior  or  suspensory  ligament  of  the  malleus  is  a  slender,  fibrous  band 
which  is  attached  to  the  outer  part  of  the  roof  of  the  tympanum  and  to  the  highest 
part  of  the  head  of  the  malleus.  It  limits  downward  and  outward  movement  of 
the  head  of  the  malleus  and  inward  rotation  of  the  manubrium  of  that  bone. 

The  anterior  ligament  of  the  malleus  is  a  strong,  fibrous  band  wliich  sur- 
rounds the  processus  gracilis  of  the  malleus.  It  is  attached  to  the  anterior  wall  of 
the  tympanum  around  the  Glaserian  fissure,  and  to  the  anterior  aspect  of  the  head 
and  neck  of  the  malleus.  It  limits  movement  of  anj'  amplitude  except  in  a  for- 
ward direction.  It  occasionally  contains  muscular  fibers,  and  has  been  described 
as  the  1(1. rotor  tijmpani  muscle. 

The  external  ligament  of  the  malleus  is  fan-shaped.  Its  apex  is  attached  to 
the  neck  of  the  malleus,  ami  its  base  to  the  margins  of  the  notch  of  Rivini.  It 
limits  outward  rotation  of  the  handle  fif  tlie  malleus. 

The  internal  ligament  of  the  malleus  is  the  sheath  of  the  tendon  of  the 
tensor  tympani  muscle,  and  extends  from  the  ti])  of  the  processus  cochleariformis 
to  the  margins  (if  tiie  insertion  of  the  tmisor  tymjiani  tendon,  whieh  is  near  the 
root  (if  tile  liaiidle  of  the  malleus  on  its  inner  surface.  It  limits  outward  move- 
ment of  the  iiandle  of  the  malleu.s. 

Tile  ligament  of  the  incus  is  a  sliort.  thick  l>aiid  wliieli  attaches  the  ex- 
tremity of  Die  short  process  of  the  incus  to  the  posterior  wall  of  the  tympanum 
near  the  orifice  of  the  mastoid  antrum. 


THE   OHdAX   OF  HEARING.  425 

The  capsular  ligaments  ^urinmul  \\w  articulations  bctwwn  tin-  luallcus  ami 
incus,  and  tlie  incus  and  stai^es. 

The  Muscles  of  the  Tympanum  are  the  stapedius  and  the  tensor  tympani. 

The  stapedius  muscle  takes  its  origin  from  the  interior  of  the  pyramid  ;  its 
tendon  passes  through  an  aperture  in  the  apex  of  the  pyramid,  and  is  inserted  into 
the  neck  of  the  stapes. 

Nerve  Supply. — The  nerve  su])i)ly  of  the  stapedius  muscle  is  derived  from  a 
branch  of  tlie  facial  nerve. 

Action. — It  draws  the  head  fif  the  stapes  backward,  tlius  pressing  tlie 
posterior  part  of  the  base  of  that  bone  against  the  border  of  tlie  oval  wIikIow, 
and  regulating  the  pressure  in  the  vestibular  contents  or  perilymph  and  cndo- 
lymph. 

The  tensor  tympani  muscle  is  larger  than  the  stapedius  muscle,  and  is  situ- 
ated in  a  bony  canal  which  lies  parallel  with  the  Eustachian  tube.  It  arises  from 
the  cartilage  of  the  Eustachian  tulie,  tlie  adjacent  surface  of  the  great  wing  of  the 
sphenoid  bone,  and  the  walls  of  the  canal  in  which  it  lies.  The  tendon  of  the 
muscle  winds  around  the  end  of  the  processus  cochleariformis,  passes  outward  in 
the  tympanum,  and  is  inserted  into  the  handle  of  the  malleus  near  its  root. 

Nerve  Supply. — The  nerve  sujtiily  of  the  tensor  tympani  muscle  is  derived 
through  a  branch  from  the  otic  ganglion,  from  the  motor  root  of  the  ti'ifaeial  or 
fifth  cranial  nerve. 

Action. — It  draws  the  malleus  inward,  thus  tightening  and  steadying  the 
mcrabrana  tympani  and  compressing  the  perilymph  of  the  internal  ear.  Ab- 
normal action  of  tliis  muscle  is  one  of  the  causes  of  snapping,  buzzing,  or  ringing 
sounds  in  the  ears. 

Blood  Supply  of  the  Middle  Ear. — The  blood  supply  of  the  middle  ear  is 
derived  from  the  tympanic  branches  of  the  internal  maxillary  and  internal  carotid 
arteries,  stylo-mastoid  branch  of  the  posterior  auricular  artery,  the  petrosal  branch 
of  the  middle  meningeal  artery,  and  a  branch  of  the  ascending  pharyngeal  artery 
whirh  passes  up  the  Eustachian  tube. 

The  veins  of  the  middle  car  empty  into  the  temporo-maxillary  vein,  the  supe- 
rior petrosal  sinus,  the  lateral  sinus,  the  internal  jugular  vein,  and  the  pharyngeal 
veins ;  numerous  small  venous  channels  pass  through  the  tegmen  tymj^ani,  eom- 
municatins  with  the  veins  of  the  dura  mater.  These  veins  afford  paths  by  which 
inflammatory  processes  may  extend  from  the  tymjianum  to  the  venous  sinuses, 
internal  jugular  vein,  meninges,  and  In-ain. 

The  Lymphatics  of  the  Middle  Ear  terminate  in  the  posterior  auricular  and 
parotid  lymphatic  glands. 

Nerve  Supply  of  the  Ty.mpanum. — The  nerve  supply  of  the  tymjianum  is 


426  SURGICAL  ANATOMY. 

derived  from  numerous  sources,  for  there  are  several  nerves  which  enter  tlie  tym- 
panic plexus  of  nerves. 

The  relation  of  the  facial  nerve  to  the  tympanum  has  already  been  con- 
sidered. 

The  chorda  tympani   nerve,  a  branch  of  the  facial  nerve,  enters  the  tym- 

%  panum  through  an  opening  in   the  posterior  wall  (iter  chordffi  posterius),  passes 

>Q-    -^through  the  outer  portion  of  the  middle  ear  near  the  upper  part  of  the  tympanic 

^v%  o   membrane,  crosses  the  handle  of  the  malleus,  and  then  enters  a  small,  bony  canal 

tf  ^^    (iter  chordas  anterius)  near  the  Glaserian  fissure.     In  the  middle  ear  it  is  covered 

by  the  tympanic  mucous  membrane.     Involvement  of  this  nerve  in  otitis  media 

may  lead  to  abnormalities  of  the  sense  of  taste  on  one  side  of  the  anterior  portion 

of  the  tongue. 

The  tympanic  plexus  of  nerves  ramifies  in  the  grooves  on  the  promontory 
and  inner  wall  of  the  tymitanuni,  and  supplies  the  mucous  membrane  of  the 
tympanum.  It  is  formed  l)y  the  tympanic  branch  of  the  glosso-pharyngeal  nerve, 
a  branch  of  the  great  superficial  petrosal  nerve,  a  branch  of  the  small  superficial 
petrosal  nerve,  and  the  small  deep  petrosal  nerve. 

Tlie  tympanic  branch  of  ilie  glosso-pharyngeal  nerve  arises  from  the  petrous 
ganglion  of  the  glosso-pharyngeal  nerve,  and  passes  into  the  tympanum  througli  a 
foramen  in  the  floor  near  the  inner  wall  of  the  tympanum. 

The  branch  of  the  great  superficial  petrosal  nerve;  which  is  derived  from  the 
facial  nerve,  passes  into  the  tympanum  through  a  foramen  in  the  inner  wall  of 
that  cavity  just  anterior  to  the  oval  window. 

The  bnnirh  of  tlie  small  superficial  petrosal  nerve,  which  is  also  derived  from 
the  facial  nerve,  enters  the  tympanum  near  the  canal  for  the  tensor  tymiiani 
muscle. 

The  small  deep  petrosal  nerve,  or  tympanic  branch  of  the  carotid  plexus  of  the 
sympathetic  nerve,  enters  the  tympanum  through  the  carotico-tympanic  canal. 

Tiie  motor  nerves  to  the  tensor  tympani  and  stapedius  muscles  have  already 
been  described. 

Otitis  media  and  dentition. — Acute  otitis  media  is  frequently  associated  with 
eruption  of  the  teeth,  and  is  also  believed  to  result  from  reflected  irritation  pro- 
duced by  carious  or  by  artificial  teeth.  This  complication  of  dentition  may  be 
explaiiu'd  l)y  tlie  connection  existing  between  the  nerves  which  su2:)ply  the 
tynipiinuiii  ;ind  tliose  supplying  the  teeth.  The  great  superficial  petrosal  nerve 
communicates  with  the  tympanic  plexus  of  nerves  and,  through  the  Vidian  nerve, 
joins  Meckel's  ganglion,  which  is  associated  with  the  superior  maxillary  nerve. 
The  nerves  to  the  upper  teeth  are  derived  from  the  superior  maxillary  nerve. 
The    small    superficial    petrosal  nerve    communicates  with    the  tympanic  plexus 


PLATE  CV. 


Superior  semicircular  canal 


Ampullae 


First  turri 
of  cochlea 


Cupola  of  cochlea' 


Vestibule 
Fenestra  ovalis  Fenestra  rotunda 


Posterior  semic'rcular 
canal 


External  semicircular  canal 


EXTERNAL  VIEW  OF  BONY  LABYRINTH,  OR  COCHLEA  AND  SEMICIRCULAR  CANALS. 

4-27 


PLATE  CVI, 


Lamina 


Posterior  semicircular  canal 
External  semicircular  canal 


Superior  semicircular  cana 


or  and 

nals 


tibuli 


Orifice  of  aqueductus  cochleae 


"^XJ^ 


'%^j?»> 


INTERIOR  OF  OSSEOUS  LABYRINTH  OF  LEFT  INTERNAL  EAR, 


:!() 


THE   ORG  AX  OF  IIEMUNG.  |:U 

of  nerves,  and  joins  the  otic  ganglinn,  wliirh  is  associated  witli  the  inferior 
maxillary  nerve.  The  inferior  dental  nerve,  which  snpplies  the  lower  teeth,  is  a 
branch  of  the  inferior  niaxillarv  nerve. 


THE  INTERNAL  EAR. 

The  Internal  Ear  or  Labyrinth. — The  most  important  portion  of  the  organ 
of  hearing  consists  of  a  series  of  complex  cavities — the  l)ony  labyrinth,  within 
which  is  the  menibranons  labyrinth. 

The  Bony  Labyrinth  is  made  up  of  tliree  intercommunicating  cavities, — the 
vestibule,  the  cochlea,  and  the  semicircular  canals, — which  are  lined  by  a  delicate 
periosteum. 

The  membranous  labyrinth  is  a  cast  of  tlie  bony  labyrinth,  but  is  considerably 
smaller  than  the  latter ;  between  the  two  there  is  a  .sjiace  lined  witii  endothelium 
and  containing  a  tiuid  called  the  perilymph.  The  parts  of  the  membranous 
labyrinth  are  the  utricle,  the  saccule,  the  membranous  semicircuhxr  canals,  and 
the  duct  or  canal  of  the  cochlea,  all  of  which  are  lined  witii  epithelium  and 
contain  the  endolymph. 

The  vestibule,  situated  between  tire  cochlea  and  semicircular  canals,  is  an 
ovoid  bony  cavity,  the  antero-postei'ior  diameter  of  which  is  about  five  millimeters, 
or  one-fifth  of  an  inch.  On  the  outer  or  lateral  wall  is  the  oval  uindow  in  com- 
munication with  the  tympanum  ;  as  previously  stated,  this  is  closed  in  the 
natural  state  by  the  base  of  the  stapes  and  the  periosteal  lining  of  the  vestibule. 
At  the  anterior  portion  of  the  inner  or  median  wall  is  a  round  depression,  the 
fovea  ]i/inispherica,  the  bottom  of  M'hicli  is  pierced  by  numerous  small  openings 
for  the  transmission  of  the  vestibular  branch  of  the  auditory  nerve.  Posterior  to 
the  fovea  hemispherica  is  a  vertical  crest,  the  crista  vcstihull.  In  the  posterior 
portion  of  the  inner  wall  is  the  small  opening  of  the  aqueductus  vestibuli,  a  canal 
which  extends  to  the  posterior  surface  of  the  petrous  portion  of  the  temi^oral  bone, 
and  lodges  the  ductus  endolymjDhaticus  and  a  minute  vein.  At  the  lower  and 
anterior  portion  of  the  vestibule  is  the  comparatively  large  opening  leading  to  the 
scala  vestibuli  of  the  cochlea.  In  the  posterior  portion  of  the  vestibule  are  the 
five  round  openings  of  the  semicircular  canals.  On  the  roof  of  the  vestibule  is  an 
oval  fossa,  the  fovea  hemiellipfica. 

The  semicircular  canals,  tln-ee  bony  tidies  about  one-twentieth  of  an  incli, 
or  one  and  one-fourth  millimeters,  in  diameter,  are  situated  behind  the  vestibule. 
The  superior  semicircular  canal  lies  nearly  in  the  sagittal  plane  of  the  body,  the 
posterior,  in  the  coronal  plane,  and  the  external,  in  a  transverse  plane  ;  conse- 
Cjuently  they  occupy  positions  about  at  right  angles  to  one  another.     Each  forms 


// 


432  SURGICAL  ANATOMY. 

more  than  a  semicircle,  and  upon  one  extremity  of  each  canal  is  an  enlargement, 
the  ampulla.  They  open  by  five  orifices  into  the  vestibule,  as  the  non-ampulkited 
extremities  of  the  superior  and  posterior  canals  join,  and  have  a  common  orifice. 
From  the  positions  of  these  canals  in  the  sagittal,  coronal,  and  transverse  planes, 
it  may  be  inferred  that  the\'  are  in  some  way  associated  with  the  maintenance  of 
ecjuilibrium.  The  occurrence  of  vertigo  from  increased  pressure  in  the  perilymph 
and  endolymph  increases  the  probability  of  this  theory. 

The  cochlea  is  situated  anterior  to  the  vestibule.  When  isolated  from  the  in- 
vesting bony  substance  it  appears  as  a  cone,  the  apex  of  -which  looks  outward  and 
somewhat  downward  and  ibrward.  The  hase  is  perforated  by  numerous  foramina 
for  branches  of  tiie  auditory  nerve,  and  is  directed  toward  the  meatus  auditorius 
internus.  The  base  is  nearly  two-fifths  of  an  inch,  or  ten  millimeters,  in  diameter, 
and  the  height  of  the  cone  is  about  one-fourth  of  an  inch,  or  six  millimeters.  The 
cochlea  consists  of  a  nearly  horizontal  central  axis,  the  modiolus  or  columnella, 
around  which  is  wound  a  spiral  tube,  in  a  manner  similar  to  the  spirals  in  certain 
snail  shells.  The  modiolus  has  numerous  canals  in  its  interior  for  branches  of  the 
auditory  nerve  ;  the  largest  is  the  canalis  caitralis  modioli.  The  spiral  canal 
diminishes  in  diameter  as  it  approaches  the  apex  of  the  cochlea,  makes  two  and 
one-half  turns  around  the  axis,  and  terminates  in  a  closed  extremity,  the  cupola. 
Projecting  into  the  spiral  canal  from  the  modiolus  is  the  bony  lamina  spiralis, 
which  does  not  reach  the  outer  wall  of  the  cochlea.  From  the  free  border  of  the 
lamina  sjjiralis  or  near  it  two  membranes  extend,  in  the  natural  state,  the 
membrana  basilaris  and  the  membrane  of  Beissner.  These  two  membranes  are 
connected  with  the  outer  wall  of  the  cochlea  and  inclose  between  them  the  cochlear 
duct,  or  scala  media  ;  they  are,  in  fact,  two  parts  of  the  membranous  cochlea.  By 
the  bony  lamina  spiralis  and  the  two  membranes  just  alluded  to  the  spiral  canal 
is  divided  into  three  parts  :  the  scala  tympani  and  the  scala  vestibuli,  between  which 
is  the  scala  media. 

The  scala  tympani  is  on  the  basal  side  of  the  lamina  spiralis,  and  opens  into 
the  tympaiu;m  at  the  fenestra  rotunda,  though  in  the  natural  state  this  opening  is 
closed  by  the  membrana  tympani  secundaria.  The  scala  vestibuli  is  on  the  opposite 
side  of  the  lamina  spiralis,  and  opens  into  the  vestibule.  These  two  scahe  com- 
municate witli  eacii  other  by  an  opening  at  the  summit  of  the  cochlea,  known  as 
the  helicotrema ;  thej^  contain  the  perilympli.  The  perili/inpJi  is  in  comnumication 
with  the  subaraclinoid   space  of  the  brain  along  the  sheatli  of  the  auditory  nerve. 

The  Membranous  Labyrinth,  the  earliest  formed  and  therefore  the  oldest  part 
of  the  organ  of  liearing,  lies  within  the  osseous  labyrinth,  from  which  it  is 
separated  in  most  places  by  the  perilymph.  It  contains  the  endolymph  and  the 
terminations  of  the  auditory  nerve,  and  it  is  lined  by  epithelium. 


s— 


II— -38 


PLATE  CVII. 


Cupola 


Lamina  spiralis 


Modiolus 


Aqueductus  cochlea 


INTERIOR  OF  OSSEOUS  PORTION  OF  COCHLEA. 
484 


PLATE  CVIII. 


Lamina  spiralis 


a  vcstibuli 


Aqueductus  cochleae 


Scala  tympani 


I  trmination  of  internal  auditory  meatus 
Modiolus 
Central  canal  of  the  modiolus 


SECTION  OF  OSSEOUS  PORTION  OF  COCHLEA. 
435 


THE  ORGAX  OF  HEARING.  437 

In  the  vestibule  are  I'ouml  two  vesicles,  the  utricle  ainl  tlie  saccule,  the 
former  lying  partly  in  the  fovea  hemielliptica,  and  the  latter  in  the  fovea  liemi 
spherica.  The  membranous  semicircular  canals  open  into  the  utricle  by 
orifices.  Filaments  of  the  vestibular  branch  of  the  auditory  nerve  ai'e  distributed 
to  a  thickened  portion  of  the  walls  of  the  utricle  which  contains  calcareous  masses, 
the  otoliths.  The  saccule,  which  is  smaller  than  the  utricle,  receives  branches  of 
the  auditory  nerve  through  the  perforations  in  the  fovea  hemispheriea ;  as  in  the 
utricle,  these  nerves  are  distributed  to  a  thickened  portion  of  the  wall  of  the  cavity, 
which  is  covered  with  otoliths.  Passing  from  tlie  saccule  along  the  aqueductus 
vestibuli  is  a  slender  tube,  the  ductus  endolymphaticus,  which  expands  into  the 
saccus  endolymphaticus,  a  blind  pouch  which  lies  on  the  posterior  surface  of 
the  petrous  portion  of  the  temiwral  bone  beneath  the  dura  mater ;  this  canal  is 
joined  by  a  small  tube  from  the  utricle,  and  thus  the  two  portions  of  the  mem- 
branous vestibule  are  brought  into  direct  communication.  The  saccule  communi- 
cates  with  the  scala  media  ol"  membranous  labyrinth  of  the  cochlea  by  means  of  a 
short  tube,  the  canalis  reuniens. 

The  membranous  semicircular  canals  are  about  one-fourth  the  diameter  of 
the  osseous  canals  in  which  they  lie  ;  their  extremities  are  ampullated. 

The  membranous  cochlea,  cochlear  duct,  or  scala  media,  lies  between  the 
scala  tympani  and  scala  vestibuli,  as  already  stated.  It  follows  the  windings  of 
the  spiral  tube  of  the  cochlea,  and  ends  blindly  at  both  extremities,  though  near 
its  basal  end  it  communicates  with  the  saccule  by  the  canalis  reuniens.  Within 
the  scala  media  is  found  the  organ  of  Corti,  a  complex  arrangement  of  modified 
epithelial  cells  to  which  the  final  ramifications  of  the  cochlear  branch  of  the  audi- 
tory nerve  are  distributed.  The  description  of  the  more  minute  structure  of  the 
internal  ear  is  not  within  the  province  of  this  book,  and  for  these  details  the 
reader  is  referred  to  works  on  sj^stematic  anatomy  and  histology. 

Aural  vertigo  is  indicated  by  ringmg  in  the  ears  or  head,  dizziness,  reeling, 
and  nausea  and  vomiting  in  succession.  It  is  produced  by  abnormal  increase  of 
pressure  in  the  membranous  labyrinth.  Cerumen  or  instillation  of  cold  licpiids 
into  the  external  auditory  meatus  may  produce  this  symptom,  and  it  may  result 
from  abnormal  conditions  in  the  middle  ear  and  reflected  irritation  in  gastric 
catarrh.     Aural  vertigo  has  been  termed  Meniere's  disease. 

Blood  Supply. — The  blood  supply  of  the  internal  ear  is  derived  from  the 
auditory  artery,  a  branch  of  the  basilar,  which  enters  the  internal  auditory 
meatus  with  the  auditory  nerve,  and  divides  into  branches  for  the  cochlea 
and  vestibule. 

The  veins  which  drain  tlie  internal  ear  are  the  vena  aqueductus  cochlea  and 
vena  aqueductus  vestibuli.     The  vena  aqueductus  cochlea  receives  the  veins  of  the 


438  SURGICAL  ANATOMY. 

cochlea,  passes  through   the  aqueductus  cochlete,  and   empties  into  tlie   internal 
jugular  vein.     The  vena  aqueductus  vestibuli  receives  the  veins  from  the  vesti- ' 
bule  and  semicircular  canals,  and  empties  into  the  superior  petrosal  sinus. 

The  Lymphatics  of  the  Internal  Ear  terminate  in  the  tympanic  and  intra- 
cranial lymphatic  vessels. 

The  Auditory  Nerve  is  the  nerve  of  the  special  sense  of  hearing.  In  the 
internal  auditory  meatus  it  divides  into  two  branches,  the  cochlear  and  the 
vestibular  ;  the  former  is  distributed  to  the  cochlea,  and  the  latter  to  the  walls  of 
the  membranous  vestibule  and  ampullse  of  the  semicircular  canals. 


THE  MEMBRANES  AND   VESSELS    OF   THE  BRAIN. 

The  dura  matei",  the  meningeal  vessels,  the  sinuses  of  the  dura  mater,  and 
the  mode  of  exit  of  the  cranial  nerves  from  the  cranial  cavity  are  described  in 
volume  I,  pages  568  to  599.  We  now  resume  the  study  of  the  brain,  the  dissec- 
tion of  which  has  been  facilitated  by  one  of  the  processes  for  preserving  and 
hardening  that  organ. 

THE  ARACHNOID. 

The  Arachnoid,  the  second  of  the  three  membranes  of  the  brain,  is  interme- 
diate in  position  between  the  dura  mater  and  the  pia  mater.  It  envelops  the 
brain,  and,  like  the  dura  mater,  sends  processes  into  the  longitudinal  and  trans- 
verse fissures,  between  the  hemispheres  of  the  cerebellum,  and,  to  a  slight  extent, 
into  the  fissure  of  Sylvius.  It  also  surrounds  the  nerves,  forming  tubular  sheaths 
for  them  as  far  as  their  points  of  exit  from  the  skull.  Unlike  the  pia  mater, 
it  does  not  dip  into  the  sulci  or  fissures  between  the  convolutions,  but  passes 
directlj-  from  one  convolution  to  the  other,  bridging  over  the  sulci.  It  forms  a 
loose  investment  for  the  brain,  and  is  continued  downward  over  the  sjnnal  cord. 
Being  a  serous  membrane,  it  jn-esents  to  the  naked  eye  a  smooth,  polished  surface. 
It  is  connected  liy  delicate  coimective  tissue  with  botli  the  dura  mater  and  pia 
mater,  but  much  more  intimately  with  the  lattei'. 

The  connection  between  the  arachnoid  and  the  pia  mater  makes  the  inde- 
pendent removal  of  the  arachnoid  very  difficult.      The  arachnoid  and  pia  mater 


PLATE  CIX. 


Posterior  semicircular  canal 


Scala  media  of  cochlea 


Superior  semicircular  canal 
Ampullae 


Saccule 


Canalis  reuniens 

Utricle 
Ductus  endolymphaticus 

Ampulla 
F>ternal  semicircular  canal 


DIAGRAM  OF  MEMBRANOUS  LABYRINTH, 
439 


THE  }fF.MnRAM':s  AM>   VESSELS   OF  THE  BRA IX.  441 

can  be  separated,  luiwrvrr,  Ky  intlatiii^-  tlu>  suUaracliiuiid  simcc  with  air  liy  means 
of  a  lilowiiipe. 

The  Subdural  Space. — The  araelnuiid  was  I'ormerly  deseril)ed  as  eonsisting  of 
two  hiyers — a  parietal  layer,  lining  the  inner  .■'nrface  of  the  dura  mater,  and  a 
visceral  layer,  reflected  over  the  Inain  :  in  tiiis  respect  it  was  said  to  resemble 
serous  membranes  elsewhere.  It  is  now  regarded  as  consisting  of  but  one  layer. 
The  space  between  the  dura  mater  and  the  arachnoid  is  known  as  the  subdural 
apace,  and  contains  a  small  amount  of  fluid  ;  this  space  was  formerly  styled  the 
cavity  of  the  arachnoid  ;  it  does  not  communicate  with  the  subarachnoid  sjmce  or 
with  the  ventricles. 

The  Subarachnoid  Space. — Tiie  space  between  the  arachnoid  and  the  jtia 
mater  is  known  as  the  subarachnoid  space ;  it  is  most  jironounced  at  the  base  of 
the  brain.  Here  the  arachnoid  membrane  is  thicker  than  elsewhere,  and  bridges 
over  the  interval  between  the  temporo-sphenoid  lobes  and  the  space  between 
the  hemispheres  of  the  cerebellum,  partially  occupied  by  the  medulla  oblongata. 
By  the  intervention  of  tlie  pons  this  general  subarachnoid  space  is  subdivided 
into  the  anterior  and  the  2^osterior  space.  The  posterior  space  connnunieates 
with  the  subarachnoid  space  of  the  spinal  cord  and  with  the  fourth  ventricle 
of  the  brain  through  a  small  oi)ening  in  the  r6of  of  the  latter  called  the 
foramen  of  Magendie,  and  tln'ough  two  other  apertures — the  foramina  of  Kcij  and 
Retzius — which  are  located  at  each  lateral  recess  of  the  fourth  ventricle.  This 
space  contains  the  cerebro-spinal  tliiid  ;  l>ecause  of  this  fact  the  lirain  may  be 
said  to  lie  on  a  water-bed.  Projecting  into  this  space  are  seen  the  larger  blood- 
vessels on  their  way  toward  tlie  l)raiu  ;  the  lymphatics  of  the  Ijrain  and  spinal 
cord  empty  into  this  space,  which  is  in  connnunication  with  the  perilymph  of 
the  internal  ear  and  witli  the  lymphatics  of  the  nose. 

Subarachnoid  Cisterns  is  the  name  given  to  the  more  capacious  i)ortions  of 
the  subarachnoid  space,  the  largest  being  the  cisterna  magna,  situated  between  the 
adjacent  surfaces  of  the  medulla  oblongata  and  cerebellum.  The  cisterna  magna 
is  the  upward  continuation  of  the  posterior  portion  of  the  spinal  subarachnoid 
space.  The  anterior  portion  of  the  spinal  subarachnoid  space  is  continued  upon 
the  anterior  surface  of  the  medulla  oblongata  and  pons  as  the  cisterna  pontis,  and 
communicates  freely  around  the  medullo-pontine  furrow,  or  sulcus,  witli  the 
cisterna  magna,  which  is  situated  above  and  behind  the  medulla  oblongata.  The 
cisterna  basalis  is  that  part  of  the  subarachnoid  space  situated  between  the  ti])s 
of  the  temporo-sphenoid  lobes  and  the  crura  cerebri,  and  in  front  of  the  pons ; 
into  it  project  the  circle  of  Willis  and  the  vessels  connected  with  this  circle. 
Laterally,  the  cisterna  basalis  extends  into  the  Sylvian  fissures  ;  while  anteriorly 
it  extends  into  a  minor  space  in  front   of  the  optic  chiasm,   and   tiience  further 


442  SURGICAL  ANATOMY. 

forward  into  the  great  longitudinal  fissure.  Another  large  space  is  found  above 
the  corpus  callosum  ;  in  the  pia  mater  at  the  bottom  of  this  space  are  the  anterior 
cerebral  arteries.  Between  the  superior  vermiform  process  of  the  cerebellum 
and  the  corpora  quadrigemina  is  an  additional  space,  which  contains  the  veins 
of  Galen.  These  spaces  communicate  very  freely  with  one  anotlier,  and  witli  the 
fourth  ventricle,  as  stated. 

The  Cerebro-spinal  Fluid  is  a  serous  fluid,  Ijut,  unlike  ordinary  serum,  it  is 
not  coagulable.  This  fluid  assists  in  jDrotecting  the  brain  and  spinal  cord  from 
violent  shocks  and  vibrations.  It  is  secreted  b}'  the  cells  of  the  ependyma  over 
the  fringe-like,  vascular  processes  of  the  choroid  plexus,  and  slightly  hy  the  cells 
of  the  arachnoid.  However,  it  is  chiefly  derived  from  the  choroid  plexuses  of  the 
lateral  ventricles,  and  to  a  less  extent  from  the  choroid  plexuses  of  the  third 
and  fourth  ventricles.  The  fluid  passes  from  the  lateral  ventricles  to  the  third 
ventricle  through  the  foramina  of  Monro,  from  the  third  to  the  fourth  ventricle 
through  the  arpieduct  of  Sylvius,  and  from  the  fourth  ventricle  through  the  fora- 
mina of  Magendie,  Key,  and  Retzius,  to  the  subarachnoid  space  of  the  brain  and 
spinal  cord  ;  some  of  the  cerebro-spinal  fluid  passes  directly  from  the  fourth  ven- 
tricle to  the  central  canal  of  the  spinal  cord.  This  constitutes  the  course  through 
which  the  cerebro-spinal  fluid  circulates,  and  equalizes  the  intra-cranio-spinal 
pressure.  By  exudation  of  plastic  lymph  at  the  base  of  the  brain,  meningitis, 
especially  the  tuljercular  variety,  may  cause  obstruction  of  the  foramina  of  Magen- 
die, Key,  and  Retzius,  and  produce  dropsy  or  hydrocele  of  the  ventricles  {internal 
hydrocephalus) ;  hence,  tapping  of  the  lateral  ventricles,  which  is  sometimes  prac- 
tised in  these  cases,  can  give  but  temporarj'  relief  Asi^iration  of  the  subarachnoid 
space  through  the  anterior  fontanel  or  of  the  spinal  subarachnoid  space,  for 
hydrocephalus,  is  followed  by  a  similar  result.  The  sudden  removal  of  a  large 
quantity  of  the  cerebro-spinal  fluid,  either  by  tapping  the  lateral  ventricles  or 
by  aspirating  through  the  anterior  fontanel,  is  not  without  its  dangers,  and  has 
been  followed  by  severe  convulsions.  The  normal  quantity  of  infra-cranial  lymph 
varies  in  amount  from  two  drams  to  two  ounces  (H.  Allen). 

The  cerebro-spinal  fluid  is  supposed  to  escape  from  the  subarachnoid  space  of 
the  brain  and  spinal  cord  by  way  of  the  prolongations  of  the  arachnoid  along  the 
cranial  and  spinal  nerves;  these  extensions  of  the  subarachnoid  sjiace  are  in 
communication  with  the  lymphatic  vessels  in  the  sheaths  of  those  nerves,  and  in 
this  manner  the  fluid  reaches  the  general  lymphatic  system  of  the  body.  It  is 
also  supposed  tliat  some  of  the  cerebro-spinal  fluid  escapes  by  way  of  the  Pac- 
chionian bodies  directly  into  the  sinuses  of  the  dura  mater. 

Choked  Disc. — In  tuliercnhir  or  other  foi'ms  of  inflammation  of  the  mem- 
branes at   the  base  of  tlie  lirain  willi  deposit  of  lymph,  or  in  case  of  tumor  at  the 


PLATE  ex. 


Anterior  communicating  a 
Antero-median  ganglionic  arteries 

Ophthalmic  a 

Internal  carotid  a 


Anterior  cerebral  a. 

Postero-median  ganglionic  arteries 


Antero-lateral  ganglionic  arteries 
Middle  cerebral  a. 


Superior  cerebellar  a. 
rior  inferior  cerebellar  a. 


Vertebral  a 
Posterior  spinal  a. 

Anterior-spinal  a 


Posterior  inferior  cerebellar  a, 
Posterior  meningeal  a.  J 


CIRCLE  OF  WILLIS  AND  ARTERIES  OF  BRAIN. 
444 


THE  MEMB RAXES  AXP   VESSELS   OF  THE  BRAIN.  445 

base  making  pressure,  the  .sheath  of  the  ujitic  lu'ive  becomes  distendwl,  cau-^iiig  a 
congestion  of  the  veins  of  the  optic  disc  (choked  disc),  an  important  diagnostic 
sign.  Pressure,  liowever,  does  not  suffice  to  expkiin  all  cases  of  "  choked  disc  "  ; 
in  many  cases  there  is  distinct  inflammation  of  the  optic  papilla,  .so  that  the  term 
papillitis  would  be  preferable. 

The  Lymphatics  of  the  brain  open  into  the  subarachnoid  space. 

The  Pacchionian  Bodies  are  enlargements  of  the  normal  villi  of  the  arach- 
noid;  they  project  from  the  sui'face  of  tliat  membrane-,  and  may  perforate  the 
overl3'ing  dura  mater  and  cause  absorption  of  the  bone  in  their  vicinity. 

Dissection. — The  next  step  in  the  dissection  consists  in  removing  the  arach- 
noid from  the  base  of  the  brain.  The  arteries  entering  the  cranial  cavity  to 
supply  the  brain  and  the  formation  of  the  arterial  circle  of  Willis  are  then  to  be 
carefulh'  examined. 

THE  .\RTERIES  OF  THE  BRAIN. 

The  Circle  of  Willis,  which  lies  in  the  pia  mater  and  2:)rojects  into  the  sub- 
arachnoid space,  is  formed  liy  branches  of  the  internal  carotid  and  basilar  arteries. 
It  forms  a  heptagonal  figure,  although  it  is  usually  not  exactly  symmetric.  This 
arrangement  serves  to  equalize  the  flow  of  blood  derived  from  the  two  internal 
carotid  arteries  and  the  basilar  artery.  AVitliout  this  or  some  similar  arrange- 
ment ligation  of  the  common  carotid,  internal  carotid,  or  vertebral  artery  would 
probably  alwaj's  result  in  softening  of  the  brain.  This  circle  is  formed  by 
the  two  posterioi-  cerebral  arteries,  which  are  the  terminal  divisions  of  the  basilar, 
the  two  internal  carotid  arteries,  the  two  posterior  communicatinfj  hranrhes  of  the 
jnternal  carotid  arteries,  which  connect  the  latter  with  the  posterior  cerebral 
arteries,  the  two  anterior  cerebral  arteries  (branches  of  the  internal  carotid  arteries), 
and  the  anterior  communicating  artery,  a  transA'erse  branch  which  connects  the  ante- 
rior cerebral  arteries.  This  circle  is  in  relation  with  the  several  structures  which 
are  situated  in  the  interpeduncular  space,  and  form  the  floor  of  the  third 
ventricle. 

The  arteries  which  enter  the  cranial  cavity  for  the  supply  of  the  brain  are  the 
two  internal  carotid  and  the  two  vertebral. 

The  Internal  Carotid  Artery,  one  of  the  two  terminal  branches  of  the 
common  carotid,  enters  the  cranial  cavity  by  Avay  of  the  carotid  canal,  pierces  the 
cartilage  which  fills  the  middle  lacerated  foramen,  and  ascends  by  the  side  of  the 
body  of  tlie  sphenoid  bone  along  tiie  inner  wall  of  the  cavernous  sinus.  Upon 
the  inner  aspect  of  tlie  anterior  clinoid  process  it  pierces  the  dura  mater,  gives  off 
the  ophthalmic  artery,  and  passes  between  the  optic  and  oculo-motor  nerves. 
Having    reached    the    anterior  perforated    space   at   the    inner   extremity  of  the 


446  SURGICAL  ANAT03IY. 

fissure  of  Sylvius,  it  gives  off  the  postei-ior  communicating  and  the  anterior 
choroid  arteries,  and  divides  into  the  anterior  and  middle  cerebral  arteries. 

The  Anterior  Cerebral  Artery  runs  forward  and  inward  across  the  anterior 
perforated  space  and  the  lamina  cinerea,  and  between  the  optic  and  olfactory 
nerves,  to  reach  the  longitudinal  fissure.  Here  it  is  joined  to  the  anterior  cerebral 
artery  of  the  opposite  side  by  a  transverse  branch,  the  anterior  communicating 
artery.  It  now  curves  around  the  genu  of  the  corpus  callosum,  and  runs  back- 
ward along  the  upper  surface  of  the  corpus  'callosum  and  at  the  bottom  of  the 
longitudinal  fissure  of  the  cerebrum  as  fiir  as  the  splenium  of  the  corpus  callosum, 
where  it  anastomoses  with  the  jiosterior  cerebral  artery. 

At  its  commencement  the  anterior  cerebral  artery  gives  off  a  few  antero- 
median branches  to  the  anterior  extremity  of  the  caudate  nucleus.  At  the  bottom 
of  the  longitudinal  fissure  it  gives  off  branches  to  the  corpus  callosum,  the  frontal 
lobe,  marginal  gyrus,  quadrate  lobule,  and  gyrus  fornicatus. 

The  Anterior  Communicating  Artery,  the  shortest  artery  in  the  body,  lies  on 
the  lamina  cinerea  in  front  of  the  optic  commissure,  and  connects  the  two  ante- 
rior cereliral  arteries  across  the  longitudinal  fissure.  It  also  gives  off  antero- 
median ganglionic  branches  which  pierce  the  lamina  cinerea,  and  a  small  branch 
to  the  anterior  extremity  of  the  corpus  callosum.  Sometimes  this  vessel  is  absent, 
when  the  two  anterior  cerebral  arteries  have  no  connection,  or  form  a  common 
trunk,  and  then  divide. 

The  Middle  Cerebral  Artery  (Sylvian),  the  largest  branch  of  the  internal 
carotiil,  runs  outward  deeply  within  the  fissure  of  Sylvius,  and  supplies  the  motor 
area  of  the  brain.  It  gives  off  branches  which  supply  the  caudate  and  lenticular 
nuclei,  the  internal  capsule,  the  optic  thalamus,  and  the  surface  of  the  brain,  a^ 
follows  :  Small  branches  which  pass  through  the  bottom  of  the  fissure  of  Sylvius 
to  the  head  of  the  caudate  nucleus ;  antero-lateral  branches,  which  pass  through 
the  anterior  perforated  space  and  supply  the  body  and  tail  of  the  caudate 
nucleus,  the  internal  capsule,  and  the  optic  thalamus ;  a  branch,  the  lenticulo- 
striate,  wliieli  passes  through  an  aperture  in  the  anterior  perforated  space  and 
supplies  the  lenticular  and  caudate  nuclei.  The  lenticulo-striate  artery  is  called 
by  Charcot  the  artery  of  cerebral  hemorrhage,  as  it  has  so  frequently  been  found 
ruptured  in  this  condition.  Finally,  opposite  the  island  of  Reil,  the  middle 
cerebral  artery  gives  off  cortical  branches  which  supplj^  the  operculum  and 
the  teni|)()i-:il  iiiid  parietal  lobes,  especially  the  supra-marginal  and  angular  gyri. 

The  Posterior  Communicating  Artery  arises  from  the  posterior  surface  of  the 
inti-rnal  rarotid,  and  runs  directly  backward,  parallel  to  and  on  the  inner  side  of 
the  oculo-motor  nerve,  to  join  the  posterior  cerebral  ai'terj'.  It  varies  in  size,  being 
sometimes  so  large  as  to  give  the  impression  that  the  posterior  cerebral  artery  is  its 


PLATE  CXI, 


Ascending  frontal  a 


Ascending  parietal  a. 


Inferior  frontal  a 
Middle  cerebral  a. 


Parieto-temporal  a. 


MIDDLE  CEREBRAL  ARTERY. 
447 


'/•///•;  .i//;.i/y.'y,'.i.v/;.s'  axd  vessels  of  the  brain.  449 

contimiation.  A  givat  (lill'orcuct'  in  tlie  size  of  the  vessels  of  the  two  sides  is 
not  inl'iv<juentiy  seen.  It  jiives  dlf  liranriies  to  the  uncinate  convolution,  with 
wliieh  it  is  in  relation,  anil  a  hrancli,  the  miildle  thalamic,  which  passes  vei-tically 
througii  the  hiiHRK'anipal  sulcus  to  the  oplic  thalanuis. 

The  Anterior  Choroid  Artery  is  given  off  hy  the  internal  carotid  just  beyond 
the  posterior  connnunicating  artery.  It  passes  backward  and  nutward  undrr  (he 
tip  of  the  teniporo-sphenoid  lulte  of  the  cerebrum,  to  enter  the  (K'scending  cornu 
of  the  lateral  ventricle  on  its  way  to  supply  the  hi}ipocampus  major,  corpus 
tiiuhriatuiu,  and  choroid  idexus. 

The  Vertebral  Artery,  a  Ijranch  of  the  iirst  portion  of  the  suhclavian,  enters 
the  cranial  cavity  by  way  of  the  foramen  magnum,  and  runs  upward  around  the 
medulla  oblongata,  between  the  hypoglossal  nerve  and  the  anterior  root  of  the 
first  cervical  or  suboccipital  nerve.  Thence  it  runs  forward  along  the  medulla 
oblongata  to  the  inner  side  of  the  hypoglossal  nerve,  and  joins  the  vertebral  artery 
of  the  opposite  side  at  the  lower  border  of  the  pons,  to  form  a  single  trunk,  the 
basilar  artery.  The  branches  given  off  from  the  vertebral  artery  within  the 
cranial  cavity  are  the  posterior  meningeal,  the  anterior  and  posterior  spinal,  and 
the  posterior  inferior  cerebellar  artery. 

The  Posterior  Meningeal  Artery  arises  from  the  vertebral  artery  opposite  the 
foramen  magnum,  and  sup[)lies  the  bone  and  dura  mater  of  the  occipital  fossa. 

Tlie  Anterior  Spinal  Artery  arises  from  the  vertebral  artery  near  its  termina- 
tion in  the  basilar,  and  joins  the  anterior  spinal  artery  of  the  opposite  side  about 
the  level  of  the  foramen  magnum.  The  common  trunk  then  runs  downward 
along  the  anterior  median  fis.sure  of  the  spinal  cord,  in  the  pia  mater.  In  its 
course  it  is  reinforced  by  successive  branches  at  tlie  level  of  each  vertebra  ;  these 
branches  are  derived  from  the  vertebral,  the  ascending  cervical,  the  intercostal,  the 
lumbar,  the  ilio-luniBar,  and  the  lateral  sacral  arteries,  all  of  which  branches  enter 
the  spinal  canal  by  way  of  the  intervertebral  foramina,  and  by  their  mesial  union 
form  a  continuous  anterior  spinal  artery  which  extends  along  the  entire  length  of 
the  anterior  median  fissure  of  the  spinal  cord. 

The  Posterior  Spinal  Artery,  smaller  than  the  anterior,  arises  from  the 
vertebral  artery  at  the  side  of  the  medulla  oblongata,  and  passes  backward  to  the 
side  of  the  posterior  surface  of  the  spinal  cord,  where  it  divides  into  two  branches, 
one  of  which  descends  behind  and  the  other  in  front  of  the  posterior  roots  of  the 
spinal  nerves.  Like  the  anterior  spinal,  it  is  reinforced  at  the  successive  vertebral 
levels  by  branches  derived  from  the  vertebral,  the  intercostal,  the  knnbar,  the 
lateral  sacral,  and  the  common  trunk  of  the  anterior  spinal  artery  by  branches 
whicli  run  around  tlie  sides  of  the  spinal  cord. 

The  Posterior  Inferior  Cerebellar  Artery,  the  largest  branch  of  the  vertebral 

S—      11-29 


450  SURGICAL  ANATOMY. 

artery,  arises  from  that  vessel  near  its  termination  (sometimes  tliis  brancli  may 
arise  from  tlie  basilar  artery) ;  it  winds  backward  around  the  medulla  oljlongata, 
between  the  pneumogastric  and  spinal  accessory  nerves;  it  then  runs  over  the 
inferior  cerebellar  peduncle  to  the  under  surface  of  the  cerebellum,  there  to 
divide  into  two  branches — an  outer  and  an  inner;  the  outer  branch  traverses  the 
under  surface  of  the  hemisphere  of  the  cerebellum,  which  it  supplies,  and  run- 
ning along  the  outer  margin  of  the  cerebellum,  it  anastomoses  M'ith  the  superior 
cerebellar  artery  ;  the  inner  branch,  practically  the  continuation  of  the  main 
vessel,  runs  in  the  groove  between  tlie  hemisphere  of  the  cerebellum  and  the 
vermiform  process,  both  of  which  it  supplies.  The  posterior  inferior  cerebellar 
artery  also  sends  branches  to  the  fourth  ventricle,  and  anastomoses  witli  the 
corresponding  vessel  of  tlie  opposite  side,  and  with  the  superior  cerebellar  artery. 

The  Basilar  Artery,  formed  by  the  union  of  the  two  vertebral  arteries  at  the 
posterior  border  of  the  pons,  runs  along  the  median  line  of  the  anterior,  or  lower, 
surface  of  the  pons  as  far  as  its  anterior,  or  upper,  border,  where  it  divides  into  its 
two  terminal  branches — the  posterior  cerebrals.  Running  on  each  side  of,  and 
almost  parallel  with,  the  basilar  artery,  are  the  sixth,  or  abducent,  nerves.  With 
tire  brain  in  situ,  the  ves.sel  lies  on  the  dorsal  surface  of  the  body  of  the  sphenoid 
bone.  Its  branches,  named  from  behind  forward,  are  the  transverse,  the  internal 
auditory,  the  anterior  inferior  cerebellar,  the  superior  cerebellar,  and  the  two 
terminal. 

The  Transverse  Arteries  are  numerous  small  branches  which  arise  from  the 
basilar  upon  each  side,  run  in  the  direction  their  name  indicates,  and  supply  the 
pons  and  tlie  adjacent  portion  of  tlie  cerebrum. 

The  Internal  Auditory  Arteries,  one  on  each  side,  spring  from  the  basilar 
artery  and  may  arise  from  the  transverse  arteries.  Each  accompanies  the  corre- 
sponding auditory  nerve  into  the  internal  auditory  meatu.?,  where  it  runs  between 
the  facial  and  auditory  nerves,  and,  reaching  the  bottom  of  the  meatus,  passes  into 
the  internal  ear. 

Tlie  Anterior  Inferior  Cerebellar  Arteries,  one  on  each  side,  arise  from  the 
basilar  artei-y  near  its  middle.  Each  artery  passes  outward  and  backward  over 
the  pons  and  the  middle  crus  of  the  cerebellum.  It  terminates  at  the  fore  part 
of  the  un<k'r  surfiice  of  the  liemisphere  of  the  cerebellum,  to  which  it  is  dis- 
tributed.     It  anastomoses  witli  tlie  ]>osterior  inferior  cerebellar  artery. 

The  Superior  Cerebellar  Arteries,  one  on  each  side,  arise  from  the  basilar  so 
near  its  liifurcation  as  to  lie  .sometimes  mistaken  for  the  posterior  cerebral  arteries. 
The  superior  cei-ebellar  artery  is  separated  from  the  posterior  cerebral  artery  by 
the  oculo-motor  nerve.  The  sujwrior  cerebellar  arteries  pass  outward  around 
llu'  cnirM   (MTcbri,   lying   ni'arly   parallrl    with   Ihi-  ]iathetic  nerves,  antl    reach  the 


PLATE  GXII, 


Anterior  communicating  a 
Posterior 

communicating  a 
Posterior  cerebral  a 


Posterior  choroid  a. 

Anterior  cerebral  a. 
.nternal  carotid  a. 
'      Anterior  choroid  a. 

Middle  cerebral  a. 


or.  of  superior   / 
cerebellar  a.' 


External  b 

'  lar  a 
Superior  cerebellar  a 
Cortical  branches  of  posterior^ 
cerebral  a 
Internal  br.of  superior 

cerebellar  a 

Basilar  a 
Anterior  spina 


Transverse  a. 
Anterior  inferior 

cerebellar  a, 
Vertebral  a. 
Posterior  inferior  cerebellar  a. 


ARTERIES  AT  BASE  OF 
452 


THE  MEM  HI!. WES  AM)   VESSELS   OE   THE  J!J:AL\.  453 

upper  surface  of  (he  cerebellum.  Here  they  diviile  iiilu  branches  which  auaslo- 
U108C  with  the  ciirresjioiiiliiig  artery  ol'  the  iip[)Osite  side  aiul  with  tlie  iufci'idr 
cerebellar  artery. 

The  Posterior  Cerebral  Arteries,  the  two  tenuiiKil  l)ranches  uf  the  basilar, 
wind  around  the  erura  eiTebri,  and,  nuining  parallel  with  the  superior  cerebellar, 
from  which  they  are  se]>arated  by  the  oculu-niotor  nerves,  reach  the  inner  surface 
of  the  posterior  part  of  the  cerebrum.  As  noted,  tluy  aie  joined  to  the  internal 
carotid  arteries  by  (he  posterior  comnmnicating  branches  of  the  latter  vessels. 
The}-  supply  the  occipital  and  (emporo-s})henoid  lobes,  and  anastomose  with 
the  anterior  and  middle  cerebral  arteries. 

Like  the  anterior  and  middle  cerebral  arteries,  the  posterior  cerebral  gives 
off  central  and  cortical  branches.  The  central  branches  are  as  follows:  8niall 
branches  which  pass  through  the  posterior  perforated  space  to  .supply  (lie  o^jfic 
thalamus  and  the  walls  of  the  third  ventricle;  tlie  posterior  choroid,  which  passes 
through  the  tran.sverse  fi.ssure  to  reach  the  velum  interpositum  and  the  choroid 
plexus  ;  while  odiers  run  to  the  optic  (halamus,  cms  cerebri,  and  corpora  quadri- 
gemina.  The  cortical  branches  are  distributed  to  the  adjacent  parts  of  the  tem- 
poral and  occipital  lobes. 

Anastomoses  of  Cerebral  Arteries. — Between  (he  cortical  and  the  central 
branches  of  (he  arteries  which  supply  the  brain  (here  is  no  anastomosis  ;  conse- 
quently, these  two  sets  of  branches  form  two  independent  systems.  The  cortical 
branches,  however,  may  and  do  anastomo.se  with  each  o(her,  but  seldom  sufficiently 
to  nourish  a  p(.irtion  of  (he  brain  from  which  (he  Ijlood  current  (hri:iugh  (he  main 
artery  supplying  it  has  been  cut  off.  In  odier  words,  (lie  cen(ral  vessels  differ 
from  the  vessels  of  (he  upper  or  lower  extremity  in  not  being  able  (o  es(ablish 
a  collateral  circulaiion  which  will  perform  the  office  of  the  principal  vessel  in 
the  event  of  its  being  .seriously  disabled.  In  (his  respect  they  resemble  (he  vessels 
of  the  lungs,  kidneys,  and  re(ina.  The  central  branches  do  not  anastomose  wi(h 
each  o(her ;  (herefore,  obs(ruc(ion  of  one  of  the  t-hief  vessels- of  the  brain  will 
result  in  softening  of  the  region  supplied  by  i(s  cen(ral  branelu-s.  wliile  softening 
of  the  region  supplied  In'  its  cortical  branches  does  not  necessarily  follow. 

Peculiarities  of  the  Arteries  to  the  Brain. — In  studying  (he  course  of  the 
four  large  ar(eries — (he  two  internal  carotids  and  the  two  vertebrals — which  enter 
(he  cranial  cavi(y  (o  supply  (he  Ijrain,  (he  dissecinr  will  <l(iublk'ss  become 
aware  of  (lie  following  peculiarides :  Firs(,  their  length  and  (ortuosKy  ;  second, 
that  the  four  ar(eries  anastomose  freely  by  means  of  (he  circle  of  Willis  ;  and, 
(bird,  (hat  (heir  numerous  and  small  branches  run  (hrough  (he  (bird  and  iiimr- 
most  membrane  of  (he  brain, — (lie  jiia  mater, — by  means  of  duplications  of  whii'h 
they  reach  the  interior  of  the  brain.     The  tortuosity  of  these  arteries  diminishes 


454  SURGICAL  ANATOMY. 

the  force  of  the  current  of  blood,  thus  lessening    the   clanger  of  apoplexy ;  and, 
through  the  circle  of  Willis,  the  pressure  in  the  four  arteries  is  equalized. 


THE  VEINS  OF  THE  BRAIN. 

The  Veins  of  the  Brain  empty  into  the  sinuses  of  the  dura  mater  (see  descriji- 
tion  of  the  sinuses,  vol.  I) ;  they  do  not  accompanj'  the  corresponding  arteries. 

The  Veins  of  the  Cerebrum  consist  of  a  superficial  or  cortical  and  a  deep  or 
central  set.  The  former  ramify  in  the  i)ia  mater  and  empty  directly  into  the 
sinuses ;  the  latter  empty  into  the  sinuses  indirectly  through  the  medium  of  the 
veins  of  Galen. 

The  Cerebellar  Veins. — Tlie  veins  which  run  over  the  superior  surface  of  the 
cerebellum  empty  into  the  veins  of  Galen  and  the  straight  sinus,  while  all  of  those 
•which  traverse  the  lower  surface  of  the  cerebellum  empty  into  the  inferior 
petrosal,  lateral,  and  occipital  sinuses. 

Absence  of  Valves. — The  veins  and  sinuses  of  tlie  brain  are  destitute  of 
valves.  Their  absence  may  be  compensated  for  in  the  superior  longitudinal  sinus 
by  the  presence  of  the  chordae  Willisii,  and  by  the  foct  that  the  veins  which  empty 
into  this  sinus  pass  from  behind  forward  in  a  direction  opposite  to  that  of  the 
blood  current,  and  that  in  entering  the  sinus  they  pass  oblic|uely  through  its  wall. 


THE  PIA  MATER. 

The  Pia  Mater,  the  innermost  of  the  three  membranes  which  cover  the  brain, 
invests  it  most  intimately,  and  sends  processes  into  all  the  fissures  of  the  cere- 
brum and  between  most  of  the  laminte  of  the  cerebellum.  It  is  the  vascular 
meml)rane  of  the  brain,  and  carries  the  minute  branches  of  the  two  internal 
carotids  and  tlie  two  vertebral  arteries,  and  the  veins  which  return  the  blood  con- 
veyed to  the  brain  by  these  vessels,  all  of  which  are  associated  by  delicate  connec- 
tive-tissue fibers.  The  author  would  liken  the  connective-tissue  element  of  the  pia 
mater  to  a  grape  arbor,  and  the  vessels  running  over  and  through  the  interstices 
to  the  grape  vine.  Added  to  the  above  are  numerous  minute  vessels,  given  off 
from  tlio  inner  surface  of  the  pia  mater,  wliich  pass  perpendicularly  into  the 
substance  of  the  l)rain. 

Only  two  of  the  ]irocesses  of  the  pia  mater  receive  special  names — the  velum 
interpositum  and  tlie  choroid  plexuses  of  the  third  and  fourth  ventricles.  Tlie 
fi)rmer  reaches  the  interior  of  the  lirain  l>v  way  of  the  transverse  fissure.  Both 
the  velum  interpositum  and  tlie  chonijd  ]ilexus  will  bo  descril)ed  witii  the  ventri- 
cles of  the  brain.     Tlu;  })oi-ti()iis  of  tlu'  pia  mater  which   cover  the  crura  cerebri 


THE   BRAIN.  455 

and   tlio  pons  have  a  (litU'rcut   aiiiuaranfo  from  tlie   rest  of  the  menihrane,  and 
present  a  dense  tibrons  strneture  wliich  contains  but  few  vessels. 

Nkrve  8ri'i>Lv. — The  pia  mater  is  supplied  with  nerves  by  branehesfrom  the 
sympatlietie,  trifacial,  and  glosso-pharyngeal  nerves. 


THE   BRAIN. 

DissECTicix. — If  the  arachnoid  and  the  [lia  mater  have  been  allowed  to  remain 
in  place  thus  far,  they  should  now  be  removed,  witli  the  exception  of  that  portion 
of  the  p*ia  mater  which  is  prolonged  inward  between  the  splenium  of  the  corpus 
collosum  above  and  the  pineal  gland  and  the  corpora  quadrigemina  below,  to 
form  the  velum  interpositum  which  is  placed  between  the  corpus  callosum  and 
fornix  above  and  the  optic  thalami,  pineal  gland,  and  corpora  quadrigemina 
below.  The  removal  of  these  membranes  exposes  the  surface  of  the  brain  ;  and  in 
dissecting  them  from  the  base  of  the  brain  care  should  be  taken  not  to  detach  any 
of  the  cranial  nerves. 

Definition  and  Weight. — The  In-ain,  or  encephalon,  is  the  intracranial  mass 
of  nervous  matter,  or  that  portion  of  the  cerebro-spinal  axis  which  is  contained 
within  the  cavity  of  the  cranium.  Its  average  weight  in  the  adult  male  is  forty- 
nine  ami  onedialf  ounces,  and  in  the  female  forty-four  ounces. 

Divisions. — The  brain  is  composed  of  four  main  jiortions  :  The  cerebrum 
(large  brain) ;  the  cerebellum  (small  brain),  which  is  second  in  size ;  the  pons 
Varolii,  which  is  third  in  size  ;  and  the  medulla  oblongata,  the  smallest,  yet  physi- 
ologically the  most  important. 

Position  of  the  Pons. — Of  these  four  portions  the  pons  Varolii  is  the  center 
around  which  the  three  remaining  portions  are  not  only  grouped,  but  to  which 
they  are  connected  in  the  following  manner :  To  the  cerebrum  by  the  crura 
cerebri,  the  cerebellum  by  the  crura  cerel)elli  (middle  peduncles  of  the  cerebel- 
lum), and  the  medulla  oblongata  by  the  anterior  pyramids  and  part  of  the  lateral 
tracts.  The  pons  rests  upon  the  posterior  surfoce  of  the  body  of  the  sphenoid  bone 
and  the  upper  part  of  the  basilar  process  of  the  occipital  bone. 

Position  of  the  Cerebrum. — The  cerebrum  occupies  all  the  upper  part  of 
the  cranial  cavity,  concealing  from  view  the  other  portions  of  the  brain  when  one 
looks  from  above,  and  rests  upon  the  floor  of  the  anterior  and  middle  fossae  of  the 
skull,  and  the  tentorium  cerebelli.  The  tentorium  cerebelli,  in  addition  to 
su[)pi)rting  tlie  cerel)rnm,  separates  it  from  the  cerebellum  and  jn'utects  the 
latter  fnim  ]>ressure  liy  the  cerebrum. 

Position  of  the  Cerebellum. — The  cerebellum  occupies  the  space  between  the 
tentorium  cerebelli  and  the  floor  of  the  posterior  cranial  fossa. 


456  SURGICAL   ANATOMY. 

Position  of  the  Medulla  Oblongata. — The  medulla  oblongata  is  continuous 
below  with  the  spinal  cord,  and  rests  upon  the  posterior  part  of  the  basilar  process 
of  the  occipital  bone. 

Contour. — The  brain  is  convex  upon  its  uj^per  and  lateral  surfaces,  and  irreg- 
ular upon  the  lower  or  liasilar  surface,  where  it  conforms  to  the  base  of  the  skull. 
The  form  of  the  surface  of  the  brain  is  largely  that  of  the  interior  of  the  cranium, 
but  not  sufficiently  so  as  to  make  phrenology  an  exact  science. 

Structures  at  the  Base  of  the  Brain. — In  dissecting  the  brain  the  most  suit- 
able article  upon  which  to  place  it  is  an  ordinary  dinner  plate  covered  with  a  thick 
layer  of  absorbent  cotton  wet  with  alcohol.  This  soft  bed  will  jn-event  the  convo- 
lutions from  being  flattened  when  the  brain  is  laid  on  its  ujiper  surface  to  study 
the  structures  forming  the  base.  These  are  the  inferior  surfaces  of  the  frontal  and 
temporo-sphenoid  lobes  of  the  cerebrum,  which  are  irregular  and  conform  to  the 
inequalities  of  the  base  of  the  .skull,  this  relation  explaining  why  contusion  of  the 
cerebrum  is  more  common  at  the  basilar  surface  of  these  lobes  than  elsewhere ;  the 
fissure  of  Sylvius,  which  separates  the  frontal  from  the  temporo-sphenoid  lobe  ;  the 
olfactory  tracts  and  bulbs  ;  the  longitudinal  fissure ;  the  corpus  callosum  and  its 
peduncles  ;  the  anterior  perforated  spaces  ;  the  optic  commissure  and  the  terminal 
parts  of  the  optic  tracts  ;  the  lamina  cinerea,  the  tuber  cinereum  and  a  part  of  the 
infundibulum — the  remaining  part,  with  the  pituitarj'  body,  liaving  lieen  de- 
scribed ;  the  corpora  alliicantia,  or  manunillary  eminences  ;  the  posterior  perforated 
space ;  the  crura  cerebri ;  the  pons  Varolii ;  the  middle  crura  of  the  cerebellum  ; 
the  lateral  hemispheres  of  the  cerebellum  ;  the  medulla  oblongata  ;  the  jwsterior 
extremity  of  the  inferior  vermiform  process  of  the  cerebellum  ;  and,  finally,  the 
roots  of  the  cranial  nerves. 

Frontal  Lobes. — The  inferior  or  orbital  surfaces  of  the  frontal  lobes  are  trian- 
gular in  .shape,  and  separated  in  front  by  the  longitudinal  fissure.  Their  bases 
are  directed  backward,  and  formed  by  the  fissure  of  Sylvius.  They  pi'esent  two 
well-pronounced  sulci  or  fissures — the  triradiate,  or  orbital,  and  the  olfactory. 
The.se,  as  will  be  seen  later,  divide  them  into  their  convolutions. 

The  Olfactory  Tract  and  Bulb  are  seen  occupying  the  olfactory  sulcus. 

Temporal  Lobes. — The  inferior  surface  of  the  temporal  or  temporo-sphenoid 
lobe,  is  slightly  convex  anteriorly  and  concave  posteriorly,  and  thus  accommodates 
itself  in  front  to  tlie  jiortions  of  the  middle  cranial  fossa  formed  liy  the  greater 
wing  of  the  sphenoid  anil  the  anterior  surface  of  the  petrous  portion  of  the  tem- 
poral bone,  and  behind  to  the  convex  tentorium.  It  presents  the  termination  of 
two  well-])ronounced  sulci — the  third  tem))oral  and  the  inferior  occipito-temporal. 

Fissure  of  Sylvius. — Between  the  iid'erior  surfaces  of  the  adjaci^nt  tVontal 
and  tcniporo-splieudid  lubes  is  seen  the  fi.ssure  of  Sylvius,  the  largest  of  tlii.'  prim- 


PLATE  CXlll. 


Olfactory  tract 
Optic  n 
Optic  tract 
Triradiate  fissure 
Anterior  perforated  space 
Cfus  cerebri 


Temporo-sphenoid 
lobe  of  cerebrum 


Olfactory  bulb 


Pituitary  body 
Optic  commissure 
,Tuber  cinereum 
Corpora  albicantia 
3rd  cranial  n, 

4th  cranial  n. 


, Anterior  pyramid  of 
-   dulla  oblongata 


Middle  peduncle  of 

cerebellum 

Posterior  perforated 

space 
Pons  Varolii 

Olivary  body 
6th  cranial  n. 
Decussation  of  pyramid 
Occipital  lobe  of  cerebrum 


sensory  root  of 

5th  cranial  n. 

Motor  root  ot 

5th  cranial  n. 


.  7th  cranial  n. 
3th  cranial  n. 
9th  cranial  n. 
I  0th  cranial  n, 
th  cranial  n. 
2th  cranial  n. 


BASE  OF  BRAIN  AND  SUPERFICIAL  ORIGIN  OF  CRANIAL  NERVES. 

458 


THE  IIRAIN.  459 

ary  fissures  of  tlic  ccrelnimi,  tlmnigh  wliidi  nui.s  the  middle  cerebral  artery  ;  into 
this  fissure  extends  the  lesser  wini;'  ot  the  sphenoid  hone,  and  from  the  fi(X)r 
of  its  anterior  portion  projeets  the  island  of  Ueil,  or  central  lobe  of  the  cerebrum. 

The  Longitudinal  Fissure  separates  the  two  frontal  lobes,  and  if  the  cerebel- 
lum is  lifteil,  the  fissure  will  be  seen  to  separate  completely  the  two  occipital  lobes. 

Corpus  Callosum. — l'>y  carefulh'  separating  the  frontal  lobes,  the  beak  or 
rostrum  of  the  corpus  callosum  will  be  seen  in  addition  to  two  white  bands, — the 
peduncles  of  the  corpus  callosum, — which  are  continued  backward  and  outward 
on  each  side  of  the  rostrum  across  the  anterior  perforated  space  to  the  commence- 
ment of  the  fissure  of  Sylvius. 

The  Anterior  Perforated  Spaces,  one  on  each  side,  are  situated  at  the  inner 
extremity  of  the  fissure  of  Sylvius.  Each  space  is  triangular  in  shape,  bounded 
in  front  by  the  frontal  lobes  and  tlie  roots  of  the  olfiictory  tracts,  externally  by  the 
apices  of  the  temporo-sphenoid  lobes  and  the  fissure  of  Sylvius,  and  posteriorly  by 
the  optic  tract.  They  are  crossed  by  the  peduncles  of  the  corpus  callosum  and  the 
external  olfactory  root ;  they  transmit  small  vessels,  chiefly  branches  of  the  middle 
cerebral  artery,  to  the  corpora  striata,  which  lie  immediately  above  the  spaces. 

The  Optic  Commissure  or  Chiasm,  from  which  arise  the  optic  nerves,  lies 
between  the  anterior  perforated  spaces  and  behind  the  anterior  inferior  jinrlion  of 
tiie  longitudinal  fissure.  It  is  formed  by  the  union  of  the  optic  tracts — two  white 
cords  seen  running  on  the  outer  side  of  the  crura  cerebri. 

The  Interpeduncular  or  Intercrural  Space  is  a  lozenge-shaped  or  quadrilateral 
area,  bounded  l)y  the  optic  commissure  in  front,  the  pons  Varolii  behind,  and  the 
optic  tracts  and  the  crura  cerebri  at  the  sides.  It  contains  the  tulter  cinereum,  the 
intra-dural  portion  of  the  infundibulum,  the  corpora  albicantia,  the  posterior  per- 
forated space,  and  the  oculo-motor  nerves.  These  structures,  except  the  last  men- 
tioned, form  the  floor  of  the  third  ventricle  with  the  exception  of  its  anterior  part, 
which  is  formed  by  the  structure  next  to  be  described — the  lamina  cinerea. 

Lamina  Cinerea. — To  expose  the  lamina  cinerea  to  the  best  advantage,  dis- 
place baclcward  the  optic  commissure,  above  which  it  lies.  It  will  then  be  seen  to 
extend  from  the  beak  or  rostrum  of  the  corpus  callosum,  to  which  it  is  attached  in 
front,  to  the  tuber  cinereum,  to  which  it  is  attached  behind.  It  is  composed  of 
gray  matter  continuous  with  the  anterior  perforated  spaces. 

The  Tuber  Cinereum  is  a  gray  eminence,  situated  behind  tlic  optic  commis- 
,sure  and  in  front  of  the  corpora  albicantia.  It  is  a  hollow  conic  process  continu- 
ous with  the  infundibulum,  Avhich  connects  the  third  ventricle  with  the  pituitary 
body.  Tlie  infundibulum  pierces  tlie  diaphragma  sella?,  a  process  of  the  dura 
mater  which  bridges  the  jiituitary  fossa. 

The  Pituitary  Body  (Hypophysis  Cerebri)  is  the  small  body  which  occupies 
the  pituitary  fossa  or  sella  turcica  and  is  covered  superiorly  by  the  diaphragma 


460  SURGICAL  ANATOMY. 

sellffi.  It  is  composed  of  an  anterior  and  a  posterior  lobe  whicli  ditfer  in  size, 
structure,  and  origin.  The  anterior  lobe  is  mucli  the  larger,  is  of  reddish-gra^^  color, 
and  is  an  isolated  process  of  the  wall  of  the  buccal  cavitj-  of  the  embryo.  The 
posterior  lobe  is  tlie  smaller,  is  lodged  in  a  depression  in  the  anterior  lobe,  is  of 
yellowish-gray  color,  and  is  a  process  of  the  brain.  It  is  the  only  j)art  of  the  pituitary 
body  structurally  continuous  with  the  inl'undiliulum,  whieh,  in  passing  from  the 
floor  of  the  third  ventricle  to  the  pituitary  bod}',  pierces  the  diaphragma  sell*. 

The  Corpora  Albicantia  (l)ulbs  of  the  fornix),  two  knobs  situated  behind  tlie 
tuber  cinereum,  are  formed  by  the  anterior  crura  of  the  fornix,  and  the  bundles 
of  Vicq  d'Azyr  from  the  oj)tic  thalamus,  wliicli  reach  the  base  of  the  brain. 

The  Posterior  Perforated  Space  is  tiiangular  in  sliape,  its  base  corresponding 
to  the  corpora  albicantia  ;  its  apex,  to  the  pons  ^"arolii ;  and  its  sides,  to  the  crura 
cerebri.  It  gives  j^assage  to  postero-median  ganglionic  branches  of  the  posterior 
cerebral  and  posterior  communicating  arteries,  which  run  to  the  optic  thalami. 

The  Crura  Cerebri,  or  cerebral  peduncles,  are  two  large  cylindric  masses  of 
white  and  gray  matter.  They  are  about  tlu'ee-fourths  of  an  incli,  or  eighteen  mil- 
limeters, long,  broader  in  front  than  liehind,  and  composed  of  the  longitudinal 
fibei's  of  the  pons  \"arolii,  together  with  some  filters  from  tire  cerebellum.  They 
commence  at  the  anterior  border  of  the  jions,  from  which  they  emerge,  and  then 
pass  forward  and  outward.  They  traverse  the  superior  occipital  foramen  in  the 
tentorium  cerebelli  in  comjtany  with  the  superior  peduncles  of  the  cerebellum,  the 
oculo-motor  and  pathetic  nerves,  and  the  basilar  artery,  and  each  enters  the  anterior 
and  inner  aspect  of  the  corresponding  temporo-sphenoid  lobe.  The  optic  tract  and 
the  pathetic  nerve  pass  around  the  outer  border  of  the  corresponding  crus  cerebri, 
while  the  oculo-motor  nerve  winds  around  the  iimer  border.  Later,  when  making 
sections  of  the  brain  to  study  the  arrangement  of  its  interior,  the  crura  cerebri  will 
be  cut  across,  wlien  the  locus  niger,  a  gray  nucleus  in  the  interior  of  each  crus,  will 
be  exposed.  The  nucleus  separates  the  fibers  of  the  crus  cerebi'i  into  two  sets:  a 
lower  and  smaller — tlie  cnisfn — and  an  upper  and  larger — the  terpnentuvi. 

The  Pons  Varolii,  or  Tuber  Annulare,  the  central  figure  in  the  group  of  the 
four  divisions  of  the  Itrain,  is  composed  cliiefly  of  white  matter,  and  is  situated 
behind  the  crura  cerebri,  in  front  of  the  medulla  oldongata,  and  between  the  hemi- 
spheres of  the  cerebellum.  It  is  about  an  inch,  or  twenty-five  millimeters,  long, 
and  n;lhcr  more  IIkih  tliis  in  width  ;  from  lis  dursal  to  its  ventral  surface  it 
measures  alxiul  Ihnv-ruurliis  of  an  inch,  or  eighteen  millimeters.  It  is  markedly 
convex  from  side  to  side  and  slightly  so  from  liefore  liackward.  and  presents 
an  antero-posterior  median  groove  which  accommodates  the  basilar  artery.  It 
consists  princi])ally  of  two  sets  of  tiber.s — a  transverse,  or  superficial,  and  a  longi- 
tudinal, or  deep,  set.  Tlie  former  set  extend  laterally  into  each  hemii^phere  of 
the  cerebellum,  forming  the  middle  jieduncU's,  or  great  ti'ansverse  commissure,  of 


Till-:  ('h'.WIAI.   .XERVES.  461 

the  ceivlK'Huin  ;  ami  the  latter  set  cxteinl  turwavd  and  outward  and  help  to 
form  the  erura  of  the  cerebrum.  INIaking  their  exit  through  the  sides  of  tiie 
j)ons,  are  the  trifacial  nerves.  The  upper  surface  of  the  pons  forms  a  jiart  of  the 
floor  of  the  fourth  ventricle. 

The  Medulla  Oblongata,  the  suiallc'st  of  the  four  divisions  of  the  brain,  is 
the  enlarged  upper  end  of  the  spinal  cord.  It  extends  from  the  lower  border  of 
the  pons,  from  which  it  is  separated  by  a  transverse  groove,  to  the  lower  b<irder 
of  the  foramen  magnum.  In  addition  to  the  medulla  oblongata  the  three 
membranes  of  the  spinal  cord,  the  vertcliral  artery,  and  the  spinal  acces.sory 
nerves  pass  through  the  foramen  magnum  of  the  occipital  bone.  Its  upper  surface 
lies  in  the  depression  between  the  hemispheres  of  the  cerebellum.  It  is  pyramidal 
in  shape  ;  about  one  and  a  cjuarter  inches,  or  thirty-twi)  millimeters,  long ;  three- 
cpiarters  of  an  inch,  or  eighteen  millimeters,  wide  at  its  broadest  part,  which  is  its 
upper  portion  ;  and  half  an  inch,  or  twelve  millimeters,  in  thickness.  It  forms 
part  of  the  sides  and  the  largest  and  most  important  part  of  the  floor  of  the  fourth 
ventricle.  Its  further  description  will  be  deferred  until  the  dissection  of  the 
cerebrum  is  completed. 

The  Hemispheres  of  the  Cerebellum  are  situated  chiefly  upon  each  side  of 
the  medulla  oblongata.  The  arrangement  of  the  gray  matter  which  forms  the 
surface  of  the  cerebellum  differs  from  that  of  the  cerebrum  in  the  following 
respects  :  In  the  cerebrum  it  is  arranged  in  convolutions  or  gj'ri  separatee]  by 
fissures,  while  in  the  cerebellum  it  is  arranged  in  clo.sely  applied  lamina?.  The 
upper  and  lower  surfaces  of  the  hemispheres  are  divided  into  lobes,  wdnch  will  be 
described  witli  the  dissection  of  the  cerebellum.  By  lifting  up  the  medulla 
oblongata,  the  depression  or  valley  between  the  two  hemispheres  of  the  cerebellum 
will  be  partly  exposed.  There  will  also  be  visible  the  inferior  surface  of  the 
middle  lobe,  or  inferior  vermiform  process,  that  portion  of  the  cerebellum  which 
forms  the  roof  of  the  fourth  ventricle  ;  projecting  beyond  the  medulla  oblongata 
is  the  jiosterior  extremity  of  the  inferior  vermiform  process  of  tlie  cerebellum, 
called  the  tuber  valvuke. 

Next  examine  the  roots  of  the  cranial  nerves  from  before  backward  in  the 
order  in  which  they  are  named. 


THE  ORIGINS  OF  THE  CRANIAL  NERVES. 

The   First    Cranial  or  Olfactory  Nerve  is  devoted   to  the  special  sen.se  of 

smell;    it  is  seen    upon  the  base  of  the  brain  as  the   olfactory  tract  and    bulb; 

in    reality,   the    olfactory    bulbs   and    tracts    represent    a    portion    of   the    l>rain, 

and  are  more  highly  developed  in  certain  of  the  lower  animals.     The  olfactory 


462  SURGICAL  ANATOMY. 

nerves  proper,  about  twenty  in  number,  wbicb  arise  from  the  olfactory  bulbs,  have 
been  divided  in  removing  the  brain  from  the  skull.  The  olfactory  tract  arises  by 
two  so-called  roots,  an  external  and  an  internal.  Tlie  external  or  long  root,  com- 
posed of  white  matter,  cro.sses  the  anterior  perforated  space  to  the  anterior  end  of 
the  hippocampal  gyrus  of  the  tem})oro-sphenoid  lobe  ;  and  the  inner  or  mesial 
root,  also  composed  of  white  matter,  passes  backward  and  inward  to  the  anterior 
extremity  of  the  gyrus  fornicatus.  Between  these  two  diverging  roots  is  a  small 
triangular  area  of  gray  matter  (trigonum  olfactorium),  which  receives  a  few  fibers 
from  the  olfactory  tract ;  when  these  fibers  are  conspicuous,  they  form  what  is 
sometimes  called  the  middle  or  gray  root.  The  tract  thus  formed  is  lodged  in 
the  olfactory  sulcus  of  the  cerebrum,  and  is  suriviunded  at  the  anterior  extremity 
by  a  small  rounded  mass  of  gray  matter,  the  oll'actory  bulb. 

Tlie  Second  Cranial  or  Optic  Nerve,  which  also  represents  a  portion  of  the 
brain,  is  the  nerve  of  vision,  and  arises  from  the  optic  commissure,  which  is 
formed  by  the  union  of  the  optic  tracts.  The  o])tic  tracts  arise  from  the  corpora 
geniculata,  the  nates  of  the  corpora  Cjuadrigemina,  and  tlie  optic  thalami.  Each 
tract  is  composed  of  three  sets  of  fibei's, — an  outer,  a  middle,  and  an  inner, — 
which  have  the  following  arrangement :  the  outer  set  passes  directly  to  the  optic 
nerve  of  the  same  side,  the  middle  set  to  the  optic  nerve  of  the  opposite  side, 
and  the  inner  set  to  the  optic  tract  of  the  opposite  side.  On  account  of  the 
course  of  the  nerve-fibers  from  the  otitic  tracts  to  the  nerves  a  lesion  of  one 
optic  tract  causes  hemianopsia,  or  obliteration  of  vision  in  the  corresponding  halves 
of  both  eyes :  as,  for  example,  a  lesion  of  the  left  optic  tract  causes  loss  of  vision  in 
the  left  half  of  Ijoth  eyes. 

The  Third  Cranial  or  Oculo-motor  Nerve  arises  superficially  from  a  groove 
on  the  inner  side  of  the  crus  cerebri,  just  anterior  to  the  pons,  and  deeply  from  a 
nucleus  in  the  floor  of  the  aqueduct  of  Sylvius.  It  is  a  motor  nerve,  and 
supplies  all  the  muscles  of  the  eyeball  except  the  superior  oblique,  the  external 
rectus,  and  radiating  fibers  of  the  iris. 

The  Fourth  Cranial,  Pathetic,  or  Trochlear  Nerve  is  the  smallest  of  the 
cranial  nerves,  and  apparently  arises  at  the  outer  side  of  the  crus  cerebri.  Its 
real  superficial  origin  is  from  the  valve  of  Vieussens,  or  superior  medullary  velum, 
immediately  behind  t;he  testes  or  posterior  pair  of  corpora  quadrigemina.  The 
deeji  origin  is  from  a  niicU'Us  in  the  floor  of  the  a<|ueduet  of  Sylvius  in  close  rela- 
tion with  the  nucleus  of  the  oculo-motor  nerve.  In  the  substance  of  the  valve  of 
Vieu.ssens  it  decussates  with  the  ojiposite  fourth  cranial  nerve.  It  then  winds 
around  the  outer  side  of  the  crus  cerebri,  and  appears  at  the  base  of  the  brain  at 
the  anterior  border  of  the  pons.  It  is  a  motor  nerve,  and  supplies  the  superior 
obli(|ue  or  ti-uchlc'iris  muscle. 


PLATE  CXIV. 


External  geniculate 
body 


Internal  geniculate 


^—7  Affected  portion  of 
Y  retinae  of  both  eyes 


Affected  optic  tract 


DIAGRAM  OF  OPTIC  TRACTS. 
463 


THE  VR AXIAL   MiliVES.  465 

The  Fifth  Cranial,  Trigeminus,  m-  Trifacial  Nerve,  the  largest  of  the  eraiiial 
nerves,  arises  lioiu  the  siiles  of  tlie  jioiis  liy  two  roots — a  larger,  posterior  or  sen- 
sory root,  and  a  smaller,  anterior  or  motor  mot.  These  roots  can  he  traeed  to  the 
floor  of  the  fourtli  ventricle  and  to  the  gray  matter  in  the  lower  part  of  the 
meihilla  ohlongata  and  in  tlie  upper  part  of  the  spinal  cord.  It  is  the  only  cranial 
nerve  which  rescmhles  a  spinal  nerve  in  arising  by  two  roots, — a  [losterior,  or 
sen.sory,  and  an  anterior,  or  motor, — and  in  having  a  ganglion  on  the  poste- 
rior root.  The  trifacial  is  a  mixed  nerve.  It  distrilnites  sensory  filaments  to 
the  dura  mater,  \na  mater,  orbit,  eyelids,  nose,  gums,  teeth,  tonsils,  palate,  sphenoid 
cells,  etlimoid  cells,  frontal  sinus,  maxillary  sinus,  nasal  fossae,  pharynx,  articulation 
of  the  lower  jaw,  ear,  parotid  gland,  scalp,  forehead,  and  face ;  gustatory  filaments 
to  the  anterior  two-thirds  of  the  tongue  ;  and  motor  filaments  to  four  of  the  muscles 
of  mastication — the  temporal,  masseter,  and  the  external  and  internal  pterygoids. 

The  Sixth  Cranial  or  Abducent  Nerve  arises  superficially  from  the  anterior 
pyramid  of  the  medulla  oblongata  and  the  interval  between  the  anterior  pyramid 
and  the  olive,  close  to  the  lower  margin  of  the  pons.  Its  deep  origin  is  from  the 
floor  of  the  fourth  ventricle.  It  is  a  motor  nerve,  and  supplies  the  external  rectus 
muscle  of  the  eyeball. 

The  Seventh  Cranial  or  Facial  Nerve  arises  as  two  portions.  The  j^ars  inter- 
media of  Wrisliciy  arises  deeplj'  from  the  forepart  of  the  nucleus  of  tlie  ninth  cranial 
nerve,  in  the  floor  of  the  fourth  ventricle.  Its  superficial  origin  is  at  the  lower 
boi'der  of  the  pons,  external  to  the  facial  nerve  proper  and  between  the  olivary  and 
restiform  bodies.  The  pars  intermedia  of  "Wrisberg  is  considered  a  portion  of  the 
glosso-pharyngeal  or  ninth  cranial  nerve,  its  nucleus  being  continuous  with  that 
f  the  ninth  cranial  nerve.  Its  fibers  are  believed  to  enter  the  chorda  tympani 
nerve.  Thus,  all  of  the  special  sensory  fibers  to  the  tongue  are  derived  from  the 
glosso-pharyngeal  nerve.  The  facial  nerve  proper  has  its  deep  origin  in  the  floor 
of  the  fourth  ventricle,  its  fibers  winding  around  the  nucleus  of  the  sixth  cranial 
nerve.  It  arises  superficially  from  the  medulla  oblongata  in  the  groove  between 
the  olivary  and  restiform  bodies.  The  facial  is  a  motor  nerve,  its  range  of  distri- 
bution is  large,  and  its  connections  with  other  nerves  are  numerous.  It  supplies 
the  stapedius  muscle,  gives  oft'  the  chorda  tympani  nerve,  the  posterior  auricular 
nerve,  the  nerve  to  the  posterior  belly  of  the  digastric,  and  a  branch  to  the  stylo- 
hyoid muscle.  In  addition  it  supplies  the  muscles  of  expression  and  the  bucci- 
nator muscle. 

The  Eighth  Cranial  or  Auditory   Nerve,  situated  immediately    beneath   or 

external  to  the  facial,  is  really  two  nerves,  and  ari.ses  deeply  from  three  nuclei, — 

Deiters',  the  accessory,  and  the  chief   nucleus. — which    are    all    situated    in    the 

medulla  oljlongata.     From  these  nuclei  two  roots  arise  which  embrace  the  restiform 

S—    11—30 


o 


466  SURGICAL  ANATOMY. 

body,  the  lateral  root  arising  principally  from  the;  accessory  nucleus,  and  the  mesial 
root  from  the  chief  nucleus  and  Deiters'  nucleus.  Its  superficial  origin  is  external 
to  that  of  the  facial  nerve — from  the  groove  between  the  olivary  and  restiform 
bodies  of  the  medulla  oblongata.  From  the  close  relation  between  the  facial  and 
auditory  nerves  at  their  exit  from  the  side  of  the  medulla  oblongata,  they  have 
been  described  as  two  separate  portions  of  the  seventh  cranial  nerve,  and  on 
account  of  their  difference  in  consistency,  (he  facial  portion  was  called  the  jiortio 
dura  and  the  auditory  portion  the  portio  mollis.  The  auditory  nerve  is  the  nerve 
of  the  special  sense  of  hearing,  and  supplies  the  internal  ear.  The  lateral  root 
is  continued  into  the  cochlear  nerve,  supplies  the  cochlea,  and  is  the  nerve  of 
the  sense  of  hearing.  The  mesial  root  is  known  as  the  vestibular  nerve  and  sup- 
plies the  vestibule  and  semicircular  canals;  it  is  a.?sociated  with  maintenance  of 
equilibrium  of  the  body. 

The  Ninth  Cranial  or  Glosso-pharyngeal  Nerve  arises  from  the  floor  of  the 
fourth  ventricle  in  common  with  the  j)neumogastric  nerve  and  the  accessory  por- 
tion of  the  spinal  accessory  nerve.  It  emerges  from  the  same  groove  in  tlie 
medulla  oblongata  as  the  facial  and  auditory  nerves,  but  below  them.  It  is 
distributed  to  the  tympanum,  the  stylo-pharyngeus  muscle,  the  mucous  mem- 
brane of  the  pharynx,  tlie  tonsil,  and  the  back  of  tlie  tongue.  The  glosso-pharyn- 
geal is  a  .sensory  and  motor  nerve,  as  well  as  the  nerve  of  the  special  sense  of 
taste,  as  it  supplies  the  circumvallatc  papilla;  at  the  l.)ack  of  the  tongue. 

The  Tenth  Cranial  or  Pneumogastric  Nerve  (nervus  vagus  or  par  vagum), 
the  longe.st  of  the  cranial  nerves,  commences  within  the  cranium,  extends  through 
the  neck  and  chest,  and  terminates  in  the  up])cr  jiart  of  the  alidomen.  It  arises 
deeply  from  the  floor  of  the  fourth  ventricle,  and  8ni)erficially  from  the  side  of  the 
medulla  oblongata  by  ten  or  fifteen  filaments,  Avhich  emerge  from  the  medulla 
oblongata  through  the  groove  between  the  lateral  column  and  the  restiform  body 

« 

and  below  the  glo.sso-pharyngeal  nerve.  The  pneumogastric  nerve  contains  both 
motor  and  sensory  fibers.  It  supjilics  the  dura  mater,  the  external  ear,  the 
jiliarynx,  tlie  larynx,  the  esophagus,  the  trachea,  the  lung.s,  the  heart,  and  some 
abdominal  viscera — viz.,  the  liver  and  stomach. 

The  Eleventh  Cranial  or  Spinal  Accessory  Nerve  consists  of  two  portions — 
an  upper  or  accessory,  and  a  lower  or  spinal.  Tlie  accessory  portion,  the 
smaller,  arises  dee|)ly  from  the  floor  of  the  fourth  ventricle  in  coiiimim  with  the 
niiilli  and  truth  cranial  nerves.  tSupri'licially,  it  arises  l»y  fine  filaments  from 
the  side  of  llie  medulla  nbldiigata  bclciw  tlic  origin  of  the  ])neumogastric  nerve, 
and  emerges  M'itli  it  through  the  same  groove.  The  spinal  portion,  the  larger, 
arises  by  several  filaments  frnm  the  side  of  the  spinal  cord,  between  the  liga- 
mentum  denticulatum  and  the  jiostcrior  roots  of  the  sjiinal  nerves  as  low  down  as 


THE  <'i:i;i:iinuM.  467 

tlio  sixth  tvrvii-;il  iui'\-e.  It  <;aiiis  t'litranro  t(i  tlic  cranial  cavity  liy  way  (if  tiie 
I'oranu'U  iiKigmini  dl'  tlir  occipital  Imiic,  ami  jiasscs  (ivit  tliiMniuii  the  iniilillc  ciun- 
partnient  nt'  tiic  jugular  or  posteriur  lacerated  Ibramen.  Tii  the  latter  situation  the 
accessory  portion  leaves  it  to  join  the  ganglion  of  the  trunk  of  the  vagus.  The 
sjnnal  accessory  is  a  scnsori-niotor  nerve,  and  supplies  the  sterno-niastoid  and 
trapezius  muscles. 

The  Twelfth  Cranial  or  Hypoglossal  Nerve  arises  superficially  i'roni  the  side 
of  the  medulla  oblongata  by  several  lilanients  Avhieh  emerge  through  tlu!  groove 
between  the  anterior  pyramid  and  the  olivary  body ;  its  deep  origin  is  from  the 
posterior  portion  of  the  floor  of  the  Iburth  ventricle.  The  filaments  of  this  nerve 
are  collected  into  two  bundles  which  perforate  the  dura  mater  separatelv  before 
passing  through  the  anterior  condyloid  foramen,  in  whicli  they  unite  to  form  the 
trunk  of  the  nerve.  The  hypoglossal  is  a  motor  nerve.  It  supplies  the  extrinsic 
muscles  of  the  tongue — viz.,  the  genio-hyo-glossu.s,  hyo-glossus,  and  the  stylo- 
glossus. Tlrrough  fibers  derived  from  the  pneumogastric  and  sympathetic  nerves 
it  suppHes  a  meningeal  branch  to  the  dura  mater,  and  through  fibers  derived 
from  the  second  and  third  cervical  nerves  it  supplies  motor  branches  to  the 
geniodiyoid,  sterno-hyoid,  sterno-thyroid,  omo-hyoid,  and  thyrodiyoid  muscles. 


THE  CEREBRUM. 

The  brain  is  now  laid  on  its  base  and  the  upper  .surface  examined.  This 
surface  is  formed  entirely  by  the  cerebrum,  and  is  seen  to  consist  of  two  halves, 
called  hemispheres,  which  are  separated  from  each  other  in  the  median  line  liy  the 
longitudinal  fissure.  This  is  one  of  the  two  largest  fissures  of  the  brain,  the  other 
being  the  horizontal  fissure. 

The  Longitudinal  Fissure. — By  gently  separating  the  hemispheres  the  longi- 
tudinal fissure  will  be  seen  to  reach  the  base  of  the  brain  both  in  front  and 
behind,  while  the  intervening  portion  is  rendered  more  shallow  by  a  transverse 
band  of  white  matter,  the  corpus  cnllomm,  which  may  therefore  be  said  to  foi'ui  its 
fioor.  Running  through  the  bottom  of  the  fissure  from  before  backward,  and  over 
the  superior  surface  of  the  corpus  callosum,  are  the  anterior  cerebral  arteries ;  this 
fis.sure  also  lodges  the  falx  cerebri  and  its  contained  sinuses,  the  superior  and 
the    inferior  longitudinal. 

The  Horizontal  Fissure. — The  ]iosterior  ends  of  the  hemispheres  of  the  cere- 
brum are  separated  from  the  cerel)ellum  l)y  the  horizontal  fissure,  the  dee])  central 
or  purely  intra-cerebral  i)ortion  of  which  is  known  as  the  fransverse  fissvre  or  the 
fissure  of  Bichaf.  The  horizontal  fissure  accommodates  the  tentorium  cerebelli  and 
its  contained  simises, — the  .straight,  the  lateral,  and  the  superior  petrosal, — while 


468  SURGICAL  ANATOMY. 

the  deep  portion,  or  the  transverse  fissure,  transmits  the  pia  mater  into  tlie  interior 
of  tlie  cerebrum,  Avhere  that  membrane  forms  the  vekim  interpositum. 

Convolutions  and  Fissures. — Tiie  surfaces  of  the  hemisplieres  of  tlie  cerebrum 
are  composed  of  convoUitions  or  gyri — elevations  of  gray  matter  wliich  are  sepa- 
rated by  fissures  or  sulci.  The  greater  the  development  of  the  hemisphere,  the 
more  numerous  are  tlie  fissures  and  convolutions,  as  the  increased  depth  and 
number  of  the  fissures  afford  additional  area  to  be  covered  with  gray  matter.  In 
studying  the  fissures  and  convolutions  from  the  fresh  brain  for  the  first  time,  that 
of  a  new-born  child  answers  best,  as  the  arrangement  of  these  structures  is  some- 
what simpler  and  agrees  better  with  the  description  of  the  brain  given  in  text-books. 

Dissection. — Before  studying  the  component  parts  of  the  brain  by  making 
sections,  it  is  better  carefully  to  study  the  surface  anatomy  of  the  hemispheres  of 
the  cerebrum.  This  entails  separating  the  cerebrum  from  the  remaining  divisions 
of  the  brain  and  carrying  an  incision  from  the  bottom  of  the  longitudinal  fissure 
through  the  median  line  of  the  corpus  callosum  and  the  structures  in  the  median 
line  of  the  cerebrum  under  the  corpus  callosum ;  this  renders  it  possible  to  ex- 
amine the  three  surfaces  of  each  hemisphere  of  the  cerebrum  to  the  best  advantage. 
To  separate  the  cerebrum  from  the  remainder  of  the  brain,  it  is  necessary  to 
divide  the  crura  cerebri  and  superior  peduncles  of  the  cerebellum,  the  latter  being 
exjDOsed  by  lifting  up  the  posterior  lobes  of  the  cerebrum.  In  order  to  do  this,  and 
also  to  obtain  the  best  idea  of  the  topograjjhic  relations  of  the  different  parts 
of  the  brain,  the  dissector  should  have  at  least  two  good  brains  at  his  disposal. 

^"ariations. — The  two  hemispheres  of  the  cerebrum  are  not  always  the  same 
in  size,  tlie  left  being  usually  the  larger.  This  is  supposed  to  be  due  to  the  fact 
that  the  blood  supply  of  this  side  of  the  brain  is  more  direct,  as  the  left  common 
carotid,  and  also  the  left  subclavian  artery,  which  gives  origin  to  the  vertebral, 
arise  directly  from  the  arch  of  the  aorta. 

Surfaces. — Each  hemisphere  of  the  cerebrum  presents  three  surfaces ;  an 
ouuT, — convex  or  lateral, — an  inner  or  nu-dian,  and  an  inferior  or  basilar.  The 
basilar  surface  rests  in  the  anterior  and  middle  cranial  fossaj  and  upon  the  tento- 
rium i-crcbcUi. 

Arrangement  of  the  Convolutions. — As  has  been  noted,  the  surfaces  of  the 
hemispheres  of  the  cerebrum  are  composed  of  gray  matter  arranged  in  folds, 
elevations,  convolutions,  or  gyri  ;  these,  in  turn,  are  separated  b}'  furrows, 
fissures,  valleys,  or  sulci  varying  in  length,  depth,  and  importance.  As  Ecker 
well  states,  the  cluef  nr  primary  coiivdhitions  are  like  great  mountain  eliains 
whose  direction  lends  to  a  region  its  characteristic  features.  The  secondary  folds 
originate  by  the  splitting  of  a  primary  convolution  into  smaller  ones  by  the  forma- 
tion of  longitudinal  furrows,  as  secondary  mountain  ridges  arise  from  the  forma- 


THE   cKHKURUM.  469 

tion  of  longitudinal  valleys.  The  deepest  fissures,  wliitii  si'|i;n:ite  tlie  principal 
convolutions  from  oacli  other,  may  be  named  the  i)riniary  ;  those  which  separate 
the  secondary  ci involutions  from  each  other,  the  secondary  ;  and,  finally,  the  ter- 
tiary convnhitiniis  are  those  little  gyri  which  jut  out  into  the  primary  fissures  from 
the  sides  of  the  principal  convolutions,  and,  therefore,  give  to  tlie  bottom  uf  the 
fissure  a  zigzag  route.  While  the  features  of  the  principal  convolutions  are  always 
arranged  with  considerable  uniformity,  numerous  variations  exist  in  the  arrange- 
ment of  the  secondary  and  tertiary'  convolutions.  There  are  several  reasons  for 
this :  one  is  that  there  are  sometimes  only  a  few  secondary  fissures,  while  in  other 
cases  there  are  quite  a  number ;  again,  in  some  cases  tertiary  convolutions  which 
are  ordinarily  invisible  come  to  the  surface ;  while  in  others,  convolutions  which 
are  usually  superficial  sink  deej^er ;  in  the  former  case  the  fissures  are  bridged 
over,  and  in  the  latter  new  convolutions  exist  in  places  where  there  usually  is 
none.  The  general  arrangement  of  the  fissures  and  convolutions  of  the  two  hemi- 
s^iheres  is  moderately  symmetric,  yet  slight  differences  always  occur. 

The  Cerebral  Fissures,  besides  being  classified  as  pi'imary  and  secondary 
fissures,  are  subdivided  into  complete  and  incomplete  fissures.  Complete  fssures 
extend  through  almost  the  entire  thickness  of  the  cerebrum,  thus  producing  eleva- 
tions in  the  lateral  ventricles  ;  examples  of  such  fissures  are  the  hippocampal  and 
portions  of  the  collateral  and  calcarine  fissures.  Incomplete  fissures  are  furrows 
of  variable  depth  which  do  not  cause  protrusions  in  the  ventricles. 

It  is  by  means  of  the  convolutions  and  fissures  of  the  brain  that  tlie  amount 
of  the  gray  matter  is  greatly  increased,  without  unduly  augmenting  the  size 
of  the  brain  ;  furthermore,  the  pia  mater  is  thus  enormously  increased  in  extent, 
because  it  follows  the  windings  of  the  gyri  and  fissures,  and  its  vessels,  which 
supply  the  cortex,  are  enabled  to  break  up  into  fine  branches  before  penetrating 
the  ])rain  tissue. 

Lobes. — Tvich  hemisphere  of  the  cerebrum  is  incompletely  divided  by  the 
deeper,  and  therefore  the  more  important,  of  the  fissures  into  the  following  parts, 
or  lol)es  :  the  frontal,  the  parietal,  the  temporal  or  temporo-sphenoid,  and  the 
occipital.  In  addition  to  these  four  lobes  there  is  a  fifth  lobe — the  central  lobe,  or 
island  of  Reil ;  but  as  this  projects  into  the  bottom  of  the  fissure  of  Sylvius,  and 
can  not  be  seen  without  drawing  apart  the  sides  of  the  latter,  it  will  be  described 
with  the  fiissures.  The  individual  lobes  are  di.stinct  from  each  other  on  certain 
surfaces  only,  while  on  other  surfaces  they  ran  into  each  other,  and  are  without 
definite  boundaries.  The  fissures  are  the  landmarks  which  guide  us  in  mapping 
out  the  hemispheres  into  districts,  or  lol)ei5,  and  also  in  locating  the  individual 
convolutions.  Hence  our  fir.st  task  in  the  .study  of  the  surfaces  of  the  hemisplieres 
of  the  cerebrum  is  to  locate  the  principal  fissures. 


470  SURGICAL  AXATOMY. 

The  Primary  Fissures  of  the  Cerebrum  are,  in  the  order  of  their  impor- 
tance, the  fissure  of  Rolando  or  the  sulcus  centralis,  the  fissure  of  Sylvius,  and  the 
parieto-occipit'al  fissure.  The  fissure  of  Sylvius  is  found  partly  on  the  inferior,  or 
basilar,  and  chiefly  on  the  outer,  convex,  or  lateral  surface  of  the  cerebrum  ;  the 
fissure  of  Rolando,  or  sulcus  centralis,  only  on  the  lateral  surftvce  of  the  cerebrum  ; 
and  the  parieto-occipital  fissure,  chiefly  on  the  median  or  inner  surface,  and 
slightly  on  the  outer  surface  of  the  cerebrum. 

The  fissure  of  Sylvius,  within  which  is  lodged  the  lesser  wing  of  the 
sphenoid  bone,  and  through  which  passes  the  middle  cerebral  artery,  commences 
on  the  basilar  surface  of  the  hemisphere  of  the  cerebrum,  at  the  anterior  perforated 
space,  in  a  depression  called  the  vallecula  Sylvii.  Thence  it  extends  outward  to 
the  external  convex  surface  of  the  cei'ebrum,  where  it  divides  into  two  limbs  :  an 
ascending  or  vertical  and  a  posterior  or  horizontal,  which  runs  backward  and 
upward  to  end  in  the  parietal  lobe.  The  main  portion  of  the  fissure  is  that  which 
occupies  the  base  of  the  brain.  The  ascending  limb  passes  upward  for  about  one 
inch,  or  twenty-five  millimeters,  into  the  frontal  lobe  in  front  of  the  precentral 
fissure,  and  is  separated  from  the  latter  by  the  posterior  part  of  the  inferior  or 
third  frontal  convolution,  which  arches  around  the  end  of  the  ascending  limb. 
Immediately  in  advance  of  the  ascending  limb  there  runs  forward  and  upward 
from  the  main  portion  of  the  fissure  a  third  limb,  the  anterior  limb.  This  limb, 
which  is  nearly  of  the  same  length  as  the  ascending  limb,  runs  directly  forward 
into  the  substance  of  the  inferior  frontal  convolution. 

The  island  of  Reil,  or  the  central  lobe,  is  seen  in  the  bottom  of  the  fissure  of 
Sylvius  at  the  angle  of  separation  of  the  ascending  and  horizontal  limbs  by  draw- 
ing widely  apart  the  sides  of  the  horizontal  limb  of  the  fissure  of  Sylvius  and  lift- 
ing the  operculum.  It  comprises  a  series  of  from  five  to  seven  small  convolutions, 
surrounded  by  a  limiting  sulcus  (sulcus  circularis  Reilii).  The  convolutions  of  this 
lolie  are  arranged  so  that  they  radiate  from  the  apex,  which  looks  downward  and 
forward.  A  fi.ssure,  the  sulcus  ceufralis  insula:,  running  in  about  the  same  direction 
as  the  fissure  of  Rolando,  divides  it  into  an  anterior  and  a  posterior  portion. 
Additional  smaller  fissures  are  seen  between  the  convolutions  of  the  island  of  Reil. 

The  operculum  is  that  portion  of  the  hemisphere  of  the  cerebrum  formed  by 
the  basse  of  tlie  inferior  frontal  convolution,  the  lower  end  of  the  ascending  frontal 
and  lower  part  of  the  ascending  parietal  convolution,  and  therefore  immediately 
overhangs  the  island  of  Reil.  The  latter  is  external  to  the  corjms  striatum,  and 
its  fissures  accommodate  some  of  the  branches  of  the  middle  cerebral  artery. 

Calloso-marginal  Fissure. — Before  attempting  to  trace  the  course  of  the  fissure 
of  IJolando,  examine  the  inner  surface  of  the  hemisphere  of  the  cerebrum  and 
locate  a  secondary  fissure  running  above  the   corpus  callosum.     it  lies  midway 


PLATE  CXV. 


Ascending  limb  of 

fissure  of  Sylvius 

Sinus  circularis  Reil 
Anterior  limb  of 
fissure  of  Sylvius 


Operculum  (elevated) 

Sulcus  centralis  insulse 

Sinus  circularis  Reilii 


Frontal  lobe 


K 


V 


■M 


!   !/ 


Gyri  operti  of  islancf  of  Reil 


1 


Temporal  lobe  (depressed) 


ISLAND  OF  REIL 
471 


PLATE  CXVI, 


'alloso  Jj 


ffa/yinal  fis 


Parle  to- 

occipital  flSS. 


Preoccipital  notcf?. 


DIAGRAM  OF  LATERAL  SURFACE  OF  CEREBRUM, 
474 


THE   CEHEIIRUM.  Alb 

between  tlie  upper  surface  of  the  latter  nml  ilic  ujipor  liordcr  of  the  hemisphere, 
and  terminates  upon  the  external  surfaeu  of  tla-  hfnii.siilu  re  near  this  border  and 
almost  opposite  the  posterior  end  of  the  corpus  callosum.  This  is  the  calloso- 
marginal  fissure. 

The  fissure  of  Rolando,  or  central  fissure,  is  tln'  most  important  of  the  three 
primary  fissures  of  the  brain,  both  from  the  surgical  and  descriptive  standpoints. 
It  runs  through  the  motor  area  of  the  cortex  of  the  cerebrum,  upon  which  so  many- 
operations  have  been  performed  in  recent  j'ears.  It  commences  at  the  upper 
border  of  the  hemisphere  of  the  cerebrum  just  external  to  the  longitudinal  fissure 
and  innnediately  in  front  of  the  terminal  part  of  the  calloso-marginal  fissure. 
From  here  it  runs  ol)li(]ue!y  downward  and  forward  Over  the  outer  surface  of  the 
hemisphere  at  an  angle  with  the  anterior  part  of  the  longitudinal  fissure  of  about 
71.5  degrees,  terminating  a  slight  distance  above  the  horizontal  limb  and  about 
one  inch,  or  twenty-five  millimeters,  behind  the  ascending  limb  of  the  fissure  of 
Sylvius.  The  calloso-marginal  fissure  is  very  rarely  bridged  over  by  a  secondary 
convolution,  and,  therefore,  there  should  be  no  difficulty  in  locating  it.  The 
fissure  of  Rolando  presents  two  more  or  less  distinct  bends,  called  its  genua  ;  the 
superior  genu,  located  at  the  junction  of  its  middle  third  and  upper  third,  has  its 
convexity  projecting  backward  ;  the  inferior  genu  is  somewhat  nearer  the  lower 
extremity  of  the  fissure,  and  its  convexity  points  forward.  In  proportion  as  the 
frontal  lobes  increase  in  size  and  the  brain  in  general  attains  higher  development 
the  fissure  runs  more  obliquely  backward  (Ecker). 

The  parieto-occipital  fissure,  the  smallest  of  the  three  primary  fissures  of  the 
cerebrum,  commences  on  the  median  surface  of  the  hemisphere  of  the  cerebrum 
about  one  and  one-half  inches,  or  thirty-seven  millimeters,  behind  the  corpus 
callosum.  It  begins  on  the  inferior  occipito-temporal  surface  at  the  junction  of 
the  apex  of  the  lingual  lobule  with  the  isthmus  of  the  gyrus  fornicatus,  and  runs 
backward  and  vijiward  to  reach  the  upper  border  of  the  hemisphere;  thence  it 
runs  outward  and  forward  on  the  external  or  convex  surface  for  about  one  inch,  or 
twenty-five  millimeters,  and  midway  between  the  fissui'e  of  Rolando  and  the  pos- 
terior extremitj'  of  the  cerebrum.  It  is  joined  by  a  secondar}^  fissure,  the  calcarine, 
the  direction  of  which  is  nearly  horizontal.  Tlie  fissure  ma}-  be  said  to  consist  of 
two  portions,  a  median  and  a  lateral,  found  respectively  on  the  median  and 
external  surfaces  of  the  cerebrum.  The  first  occipital  convolution  arches  around 
the  end  of  tlie  lateral  portion  of  the  fissure.  The  lateral  portion  of  the  parieto- 
occipital fissure  is  not  always  well  marked,  often  appearing  merely  as  a  slight 
indentation  upon  the  outer  or  convex  surface  of  the  hemisphere,  while  the  median 
portion  of  the  fissure  is  uniformly  well  developed. 

The  Frontal  Lobe,  the  largest  of  the  cerebral  lobes,  includes  that  portion  of 


476  SURGICAL  ANATOMY. 

the  hemisphere  of  the  cerehruni  in  front  of  and  aljove  the  main  jiortion  of  llie 
fissure  of  Sylvius,  and  tliat  portion  in  front  of  tlie  fissure  of  Rolando;  upon  the 
inner  surface  it  includes  the  corresponding  portion  of  the  liemis})here  ahove  the 
calloso-marginal  fissure.  There  is  generally  no  line  of  demai'cation  between  the 
frontal  and  parietal  lobes  upon  the  mesial  surface  of  the  hemisphere,  but  exten- 
sion of  the  fissure  of  Rolando  into  the  longitudinal  fissure  (a  condition  sometimes 
existing)  designates  the  posterior  limit  of  the  frontal  lobe  on  this  surface. 

The  Parietal  Lobe  includes  that  portion  of  the  lateral  surface  of  the  hemi- 
sphere of  the  cerebrum  above  the  horizontal  limb  of  the  fissure  of  Sylvius,  and  a 
line  representing  the  extension  of  the  same  limb  backward  to  meet  the  posterior 
boundary  of  the  lobe  ;  also  behind  the  fissure  of  Rolando  and  in  front  of  the  lateral 
portion  of  the  parieto-occipital  fissure.  Upon  the  inner  surface  it  includes  that 
part  of  the  hemisphere  in  front  of  the  mesial  portion  of  the  parieto-occipital 
fissure;  it  is  unlimited  in  front  on  this  surface  for  want  of  a  line  of  demarcation 
between  it  and  the  frontal  lobe,  but,  as  previously  stated,  by  extending  the  fissure 
of  Rolando  into  the  longitudinal  fissure,  its  anterior  superior  limit  would  be  repre- 
sented. The  parietal  lobe  is  only  partly  separated  behind  from  the  occipital  lobe, 
by  the  lateral  portion  of  the  parieto-occipital  fissure  and  the  transverse  occijsital 
fissure  ;  the  latter  is  a  secondary  fissure  which  is  not  always  present.  P\om  the 
temporo-sphenoid  lobe,  below,  tliere  is  no  attempt  at  complete  separation.  At  tlie 
lower  margin  of  the  lateral  .surface  of  the  hemisphere  of  the  cerebrum,  between 
the  occipital  and  temporo-sphenoid  lobes,  is  the  preoccipital  notch  produced  by 
the  impression  of  the  veins  which  enter  the  lateral  sinus.  If  a  line  be  drawn 
to  this  notch  from  the  extremity  of  the  lateral  portion  of  the  parieto-occipital 
fissure,  the  upper  part  of  this  line,  with  the  lateral  portion  of  the  fissure,  will 
about  represent  the  junction  of  the  parietal  and  occipital  lobes.  The  lower  part 
of  the  line  will  represent  the  line  of  junction  of  the  occipital  and  temporo- 
sphenoid  lobes.  This  notch  must  not  be  confounded  with  another  impression, 
sometimes  described  as  the  preoccipital  notch,  produced  by  the  superior  border  of 
the  petrous  portion  of  the  temporal  bone  (Brooks). 

The  Occipital  Lobe  includes  that  portion  of  the  convex  surface  of  the  hemi- 
sphere of  the  cerebrum  behind  the  lateral  portion  of  the  jiarieto-occipital  fi.ssure, 
and  a  line  connecting  the  extremity  of  this  fissure  with  the  preoccipital  notch. 
Upon  the  inner  surface  of  the  hemisphere  it  includes  that  part  behind  the  mesial 
portion  of  the  parieto-occipital  fissure.  Upon  the  liasilar  surfoce  there  is  no  line 
of  demarcation  between  it  and  the  temporo-sphenoid  lobe.  The  inferior  surface 
of  this  lobe  will  l)e  described  with  the  same  surface  of  the  temporo-sphenoid,  as 
two  of  the  most  imjinrtant  secondary  fissures  here  seen  occupy  both  of  these 
lobes,  and  extend  witiiuut  brcacli  of  (■(nitinuity  from  one  to  the  other. 


PLATE  CXVII 


Intraparietal  fissure 
Superior  vertical  portion  of  intraparietal  fissure 
Ascending  parietal  convolution 
Fissure  of  Rolando 
Ascending  frontal  convolution 


Superior  occipital  convolution 
Superior  occipital  fissure 
Transverse  occipital  fissure 
Parieto-occipllal  fissure 
Angular  gyrus 
Superior  parietal  convolution 
Calloso-marginal  fissure 
Suprannarginal  gyrus 


Su 
Sui 


Inferior  frontal  convolution 
Ascending  limb  of  fissure'o'5  Sylvit. 
Fissure  of  Sylvius 

Horizontal  limb  of  fissure  of  Sylvius 
'■  Superior  temporal  convolution 

Parallel  fissure 
Middle  temporal  convolution 

Middle  temporal  fissure 
Inferior  temporal  convolutiori 

Cerebellum 

Middle  occipital  fissure 

Inferior  occipital  convolution 

Middle  occipital  convolution 


EXTERNAL  SURFACE  OF  CEREBRUM. 
477 


PLATE  CXVIII. 


Superior  frontal  convolution 
Superior  frontal  sulcus 


Middle  front 
Inferior  frontal  sulcus 
Inferior  frontal  convoluti 


Longitudinal  fissure 

Fissure  of  Rolando 

Ascending  frontal  convolution 
Precentral  sulcus 


Intraparietal  sulcu 

Inferior  parietal 

convolutio 
Middle  occipital  sulcus 

Ascending  parietal  convolutio"rT 

Transverse  occipital  su 

Superior  parietal  convolution 


Superior  occipital  sulcus     Parieto  occipital  fissure 


Inferior  occipital 
convolution 

Middle  occipital  convolution 
Superior  occipital  convolution 
Calloso    marginal  fissure 


SUPERIOR  SURFACE  OF  CEREBRUM, 
480 


THE   CEREBRUM.  481 

The  Temporal  (n-  Temporo-sphenoid  Lobe  conipiisi':?  tluit  iioiticm  of  tlie 
lateral  suffaee  ol'  the  hemisphere  of  tiie  eerehruiu  helow  the  Imri/oiilal  liuili  v^ 
the  fissure  of  Sylvius,  aud  a  Hue  represeutiuj;-  its  coutiuuatiou  haekwanl,  and  in 
frout  of  tlie  lower  part  of  the  Hue  eouueetiug  the  preoceipital  uoteh  with  the 
extremity  of  the  lateral  portiou  of  the  parieto-occipital  fissure.  Upon  the  inferior 
surface  of  the  cerebral  hemisphere  it  lies  immediately  iK'hind  the  main  portion  of 
the  fissure  of  Sylvius;  it  is  not  separated  on  this  surface  fi-om  llic  oecipiial 
lobe.  A  line  drawn  from  the  preoccipital  notch  to  the  isthmus  of  the  jiyrus 
fornicatus  marks  the  line  of  union  of  the  tcmjioro-splienoid  and  occipital  l(jbes 
(Brooks). 

The  Island  of  Reil,  or  the  hfth  lobe  of  the  cerebrum,  is  described  with  the 
fissure  of  Sylvius. 

The  arrangement  of  the  jirimary  fissures  and  the  boundaries  of  the  lobes 
of  the  cerebral  hemispheres  having  been  given,  the  description  of  the  secondary- 
fissures  and  convolutions  naturally  follows.  Secondary  convolutions  fi('(|Uent!y 
bridge  these  secondary  fissures,  making  it  difficult  to  trace  them. 

The  Frontal  Lobe  is  situated  in  the  angle  between  the  vertical  and  the 
horizontal  j)lates  of  the  frontal  bone,  and  extends  backward  bey(.>nd  the  coronal 
suture.  It  is  that  jiortion  of  the  hemisphere  in  front  of  the  fissure  of  Rolando, 
anil  above  the  anterior  part  of  the  horizontal  liinl.)  of  the  fissure  of  Sylvius.  Like 
the  cerebral  hemisphei'e,  it  has  three  surfaces  :  a  lateral  or  convex,  an  inferior  or 
basilar,  and  an  inner  or  mesial.  Upon  the  lateral  surface  are  three  secondary 
fissures :  the  superior  and  the  inferior  frontal,  the  direction  of  which  is  horizontal, 
and  the  precentral  or  transverse,  whose  direction  is  vertical.  The  ascending  and 
the  anterior  limbs  of  the  fissure  of  Sylvius  are  also  in  relation  A\itli  it.  The 
superior  and  inferior  frontal  fis-sures  run  parallel  with  the  longitudinal,  and  the 
})recentral  follows  a  course  nearly  parallel  with  that  of  the  lower  half  of  the 
fissure  of  Rolando. 

The  superior  frontal  fissure  commences  a  short  distance  in  front  of  the  fissure 
of  Rolando,  and  runs  forward  and  downward  parallel  with  the  longitudinal  fissure, 
the  gyrus  included  between  the  longitudinal  fissure  and  superior  frontal  fissure 
being  the  first  or  .superior  frontal  convolution. 

The  inferior  frontal  fissure  usually  commences  in  the  precentral  fissure,  but 
sometimes  in  front  of  it,  and  runs  forward  and  downward  about  midway  between 
the  superior  frontal  fissure  and  the  lower  liorder  of  the  frontal  lobe.  Between  the 
superior  and  the  inferior  frontal  fissure  lies  the  middle  or  second  frontal  convolu- 
tion, and  between  the  inferior  frontal  lissure  and  the  lower  margin  of  the  lobe  the 
inferior  frontal  convolution  is  situated. 

The  precentral  fissure   lies   in    front   of  and   parallel   with    the   fissure   of 
S—  ii-:;i 


482  SURGICAL  ANATOMY. 

Rolando  ;  its  lower  end  is  between  the  latter  fissure  and  the  ascending  limb  of  the 
fissure  of  Sylvius.  This  fissure  usually  consists  of  two  parts,  a  superior  and  an 
inferior  precentral  fissure,  the  former  of  M-hich  is,  as  a  rule,  continuous  with  the 
superior  frontal  fissure,  and  the  inferior  at  times  with  the  inferior  frontal  fissure. 

The  ascending  frontal  convolution  is  situated  between  the  precentral  fissure 
and  the  fissure  of  Rolando,  and  extends  along  the  entire  anterior  border  of  the 
latter  fissure.  This  convolution  is  continuous  with  the  ascending  parietal  convolu- 
tion around  both  ends  of  the  fissure  of  Rolando,  immediately  behind  which  the 
latter  convolution  is  situated. 

The  superior  or  first  frontal  convolution  is  continuous  posteriorly  with  the 
ascending  frontal,  internally  with  the  marginal,  and  anteriorly  upon  the  basilar 
surface  with  the  gyrus  rectus  and  the  internal  and  anterior  orbital  convolutions. 

The  middle  or  second  frontal  convolution  is  continuous  in  front  with  the  an- 
terior orbital  convolution  and  the  anterior  extremities  of  the  superior  and  inferior 
frontal  convolutions.  Posteriorly,  it  frequently  bridges  the  precentral  fissure,  and 
joins  the  ascending  frontal  convolution. 

The  inferior  or  third  frontal  convolution  is  continuous  behind  with  the  as- 
cending frontal  convolution,  and  in  front,  upon  the  inferior  or  basilar  surface,  with 
the  anterior  and  posterior  orbital  convolutions.  Through  the  medium  of  the  an- 
terior and  ascending  limbs  of  the  fissure  of  Sylvius,  both  of  which  extend  into 
this  convolution,  it  is  divided  into  three  parts :  namelj',  that  in  front  of  the  ante- 
rior limb,  the  pars  orbitalis  ;  that  between  the  anterior  and  the  ascending  limb,  the 
pars  triangularis  (base  of  triangle  looks  upwanl)  ;  and  that  behind  the  ascending 
limb,  the  pars  basilaris  (Brooks).  This  convolution,  as  before  mentioned,  assists 
in  the  formation  of  the  operculum. 

The  inferior  or  orbital  surface  of  the  frontal  lobe  is  triangular  in  shape  ;  the 
base,  directed  backward,  is  formed  by  the  anterior  perforated  space  and  the  main 
portion  of  the  fissure  of  Sylvius.  The  apex  is  directed  forward,  and  is  formed  by 
the  curving  of  the  convolutions  in  passing  from  the  convex  to  the  orbital  surface. 
The  sides  are  formed  by  the  longitudinal  fissure  and  the  lower  border  of  the  hemi- 
sphere.    On  this  surface  are  two  secondary  fissures,  the  olfactory  and  the  orbital. 

The  olfactory  fissure  runs  parallel  with  the  longitudinal  fissure  and  a  short 
distance  external  to  it.     It  lodges  the  olfactory  tract  and  bulb. 

The  orbital  or  triradiate  fissure  is  situated  about  the  middle  of  the  portion 
of  this  surface,  which  lies  external  to  the  olfactory  fissure.  It  consists  of  a  main 
portion,  which  is  directed  forward  and  runs  nearly  parallel  with  the  olfactory  fis- 
sure, and  of  two  branches,  one  directed  backward  and  inward,  and  the  other 
outward. 

The  gyrus  rectus  is  situated  between  the  olfactory  and  longitudinal  fissures. 


PLATE  CX!X. 


Posterior  orbital  gyrus 
Internal  orbital  gyrus 
Olfactory  bulb 
Gyrus  rectus  \ 


Anterior  orbital  gyrus 
,Triradiate  fissure 


Island  Reil 


Formatio  reticularis  at  superior  portion  of  pons 
Aqueduct  of  Sylvius 


Optic  commissure 
Uncus 
Crus  cerebri 


INFERIOR  SURFACE  OF  FRONTAL  LOBE. 
483 


THE   CEREBRUM.  485 

It  is  continuous  in  front  with  the  supiTior  or  tirst  tVdiilal  convdlutidu,  ami  iutcr- 
nally  witli  thr  inarj;inal  ciinvolutidu. 

The  internal,  anterior,  and  posterior  orbital  gyri  are  located  between  the 
branches  (tf  the  trinuliate  fissure,  and  are  named  from  their  relation  to  the 
brandies  of  the  fissure.  Tliey  are  continuous  respectively  with  the  first,  second, 
and  third  fruntal  eunvnlutions. 

Inner  surface  of  the  frontal  lobe. — Upon  this  surface  are  tertiary  fissures,  the 
chief  of  which  runs  for  some  distance  jiarallel  with  the  calloso-marginal  fissure, 
and  i)artly  divides  the  convolution  of  this  surface  into  two  portions. 

The  marginal  gyrus  lies  between  the  calloso-marginal  fi.s.sure  and  the  upper 
and  anterior  margin  of  tlie  liemisphere  of  the  cerebrum.  This  convolution  com- 
mences l)elow  the  rostrum  of  the  corpus  callosum  at  the  anterior  j)eribrated  space, 
and  extends  ujiwanl  and  backward  between  the  calloso-marginal  fissure  and  tlie 
margin  of  the  hemisphere,  as  far  as  a  line  which  represents  the  continuation  of  the 
precentral  fissure  into  the  longitudinal  fissure.  It  is  continuous  along  the  margin 
of  the  liemisphere  with  the  superior  or  first  frontal  convolution. 

Tlie  Parietal  Lobe  is  that  portion  of  the  hemisphere  situated  luhiiid  the  fissure 
of  Rolando,  above  the  horizontal  liml)  of  the  fissure  of  Sylvius,  and  in  front  of  the 
lateral  limb  of  the  parieto-occipital  fissure.  The  portion  of  the  lobe  below  the 
lateral  limb  of  the  parieto-occipital  fissure  and  beyond  the  termination  of  the  hori- 
zontal limb  of  the  fissure  of  Sylvius  is  continuous  with  the  occipital  lobe  l)y  means 
of  annedant  gyri.  The  limit  of  the  parietal  lobe  behind  is  represented  by  the 
lateral  liml)  of  the  parieto-occipital  fissure,  and  a  line  previously  described,  which 
extends  from  the  end  of  that  fi.ssure  to  the  preoccipital  notch.  It  presents  two 
surfaces,  a  lateral  or  convex,  and  an  inner  or  mesial. 

Upon  the  lateral  surface  one  and  sometimes  two  chief  secondary  fissures  are 
to  be  seen.  When  but  one  fissure  is  present,  it  is  the  intra-parietal,  and  wlien  two 
fissures  are  present,  tliey  are  tlie  intra-parietal  and  the  post-central. 

The  intra-parietal  fissure  commences  above  the  horizontal  limb  of  the  fissure 
of  Sylvius,  a  short  distance  Ixdiind  the  fii5.sure  of  Rolando,  and  runs  upward, 
parallel  to  the  lower  portion  of  the  latter  fissure  ;  it  then  turns  backward,  runs 
nearly  parallel  with  the  longitudinal  fissure,  and  terminates  in  the  occipital  lobe, 
most  commonly  in  the  transverse  occipital  fissure.  The  posterior  portion  of  the 
horizontal  part  of  the  intra-pai'ietal  fissure  is  often  separated  from  the  main  fissure 
by  a  bridging  convolution. 

The  post-central  fissure,  when  [iresent,  exists  either  as  a  continuation  of  the 
ascending  liml>  of  the  intra-parietal  fissure  beyond  the  junction  of  the  ascending 
with  the  horizontal  limb,  thus  making  the  intra-parietal  fi.ssure  T  sha))ed,  or  it  is 
entirely  .separated  from  the    ascending  limb    of  the    intraparietal    fissure.       The 


486  SURGICAL   AXATOMY. 

former  is  the  arrangement  more  coiuinonly  seen.  The  post-central  fissure  runs 
parallel  to  the  upper  portion  of  the  hssure  of  Rolando  almost  to  the  longitudinal 
fissure. 

Convolutions. — Through  the  medii'im  of  the  intra-parietal  fissure  or  of  the 
intra-parietal  and  po.st-central  fissures  the  lateral  surface  of  the  parietal  lobe  is 
divided  into  three  principal  convolutions  :  the  ascending  parietal  or  po.st-central, 
the  superior  parietal,  and  the  inferior  parietal.  The  inferior  parietal  convolution 
is  further  subdivided  into  the  supra-marginal  and  angular  convolutions. 

The  ascending  parietal  or  post-central  convolution  lies  immediately  behind 
the  fissure  of  Rolando,  in  front  of  the  ascending  limb  of  the  intra-parietal  fissure, 
and  the  po.st-central  fissure  when  present,  and  above  the  horizontal  lind>  of  the 
fissure  of  Sylvius.  It  is  continuous  -with  tlie  ascending  frontal  convolution  around 
the  ends  of  the  fissure  of  Rolando,  and  with  the  superior  parietal  convolution. 
It  runs  parallel  with  the  ascending  frontal  convolution ;  its  lower  extremity 
extends  to  the  horizontal  limb  of  the  fissure  of  Sylvius,  forming  the  posterior  part 
of  the  operculum ;  its  upper  extremity  is  limited  by  the  longitudinal  fissure,  and, 
with  the  corresponding  end  of  the  ascending  frontal  convolution,  forms  the  para- 
central lobule. 

The  superior  parietal  convolution  lies  behind  the  ascending  parietal  con- 
volution, with  which  it  is  continuous.  It  is  situated  between  the  longitudinal 
fissure  and  the  horizontal  limb  of  the  intra-parietal  fissure,  and  extends  i^steriorly 
as  far  as  the  lateral  portion  of  the  parieto-occipital  fissure.  Around  the  extremity 
of  this  fissure  it  is  continuous  with  the  first  occipital  convolution  through  the 
medium  of  the  first  annectant  gyrus.  On  the  mesial  aspect  of  the  hemisphere 
it  is  continuous  with  the  quadrate  lobule  or  precuneus. 

The  inferior  parietal  convolution  lies  behind  the  ascending  limb  and  below 
the  horizontal  limb  of  the  intra-parietal  fissure,  and  above  the  horizontal  limb  of 
the  fissure  of  Sylvius.  Posteriorly  it  is  connected  with  the  second  occipital  convo- 
lutiiin  by  means  of  the  second  and  tliird  annectant  gyri,  and  also  witli  the  supe- 
rior temporal  and  the  middle  temporal  convolution.  It  is  sub<livided  into  two 
convolutions,  the  supra-marginal  and  the  angular. 

The  snpra-margiiial  convolution  includes  the  anterior  portion  of  the  inferior 
parietal  as  far  as  the  posterior  extremity  of  the  horizontal  limb  of  the  fissure  of 
vSylvius.  It  winds  around  tjiis  liml)  and  becomes  continuous  with  the  superior 
trnipdral  ciiiivuhilion  and  tlic  angular  convolution. 

Tlie  mii/iil<ii-  rniiriihition  is  tlie  posterior  portion  of  the  inferior  parietal  convo- 
lution ;  it  lies  Ixiiind  the  terminal  part  of  the  horizontal  limb  of  the  fissure  of 
Sylvius  as  it  inclines  upward.  It  winds  around  the  posterior  end  of  the  superior 
temporal  fissure,  and  becomes  continuous  with  the  second  occipital  convolution 


PLATE  CXX, 


Paracentrallobule 


Locus  niger 


Gyrus  rectus' 
Olfactory  sulcus' 


Uncus 
Optic  thalamus 


Rostrum  of  corpus  callosum   Lateral  ventricle 


MEDIAN  AND   INFERIOR  SURFACES  OF  CEREBRUM. 
•J  88 


THE   CEREBRUM.  489 

through  the  nu'diuni  of  tlir  set-ond  and  third  aunectant  gj'ri.  It  is  also  continuous 
with  tlie  middle  temporal  convolution. 

The  post-parietal  convolution. — In  some  brains  the  middle  temin)ro-sphenoid 
Jissurc  terminates  in  the  inferiur  parietal  convolution,  and  with  the  fissure  of  Syl- 
vius and  the  su])erior  temporo-sphenoid,  or  ]iarallel,  fissure  divides  this  convolu- 
tion into  three,  as  IVillows  :  that  winding  around  the  extremity  of  tlii'  Imrizdntal 
limb  of  the  fissure  of  Sylvius  forms  the  supra-marginal  gyrus  ;  that  aruvuid  the 
posterior  extremity  of  the  superior  temporo-sphenoid  fissure,  the  angular  gyrus ; 
and  that  around  the  posterior  extremity  of  the  middle  temporo-siihenoid  fissure, 
the  post-parietal  gyrus.  The  last -mentioned  convolution  is  continuous  with  the 
third  occipital  convolution  (Heath). 

Upon  the  inner  t)r  median  surface  of  the  parietal  lolie  the  terminal  ])art  of  the 
calloso-marginal  fissure,  one  of  the  most  important  secondary  fissures,  is  seen  and 
is  mentioned  in  describing  the  fissure  of  Rolando.  This  fissure  commences  below 
the  anterior  extremity,  or  rostrum,  of  the  corpus  callosum.  Thence  it  runs  parallel 
to,  and  a  short  distance  above,  the  corpus  callosum,  from  which  it  is  separated  by 
the  convolution  of  the  corpus  callosum  or  gyrus  fornicatus,  to  nearly  opposite  the 
posterior  extremity  or  splenium  of  the  corpus  callosum.  Here  it  turns  ujjward  and 
pursues  a  slightly  backward  course,  terminating  on  the  superior  border  of  the 
hemisphere  of  the  cerebi'um,  immediately  jiosterior  to  the  fissure  of  Eolando.  The 
calloso-marginal  fissure,  particularly  tlie  anti^rior  jiart,  is  frequently  bridged  over 
by  small  convolutions. 

The  subparietal  fissure  is  a  much  smaller  fissure,  Mhieh  connnences  at  the 
point  where  the  terminal  portion  of  the  calloso-marginal  fissure  begins  to  turn 
upward.  For  all  practical  purposes  it  may  be  considered  the  continuation  l)ack- 
ward  of  the  main  portion  of  the  calloso-marginal  fissure. 

The  paracentral  fissure,  not  always  jn-esent,  is  a  small  tertiary  fissure  running 
out  of  the  main  portion  of  the  calloso-marginal,  on  a  line  with  the  anterior  limit 
of  the  median  end  of  the  ascending  frontal  convolution.  AVhen  present,  it 
marks  definitely  the  po.sterior  limit  of  the  marginal  convolution. 

Convolutions. — Through  the  medium  of  the  calloso-marginal,  paracentral, 
subparietal,  and  parieto-occipital  fissures  the  inner  surface  of  the  parietal  lobe  is 
divided  into  two  lobules  or  convolutions — the  precuneus,  or  quadrate,  and  the 
paracentral,  the  former  being  posterior  to  the  latter. 

The  precuneus,  or  quadrate  lobule,  lies  between  the  median  limb  of  the 
parieto-occipital  and  the  terminal  portion  of  the  calloso-marginal  fissure  and  above 
the  subparietal  fissure. 

The  paracentral  convolution  includes  the  median  ends  of  the  ascending 
parietal  and  ascending  frontal  convolutions.     It  lies  immediately  in  front  of  the 


4yU  SURGICAL  ANATOMY. 

terminal  portion  of  the  calloso-marginal  fissure,  above  the  horizontal  portion  of 
this  fissure,  and  behind  the  paracentral  fissure,  or  a  line  representing  the  exten- 
sion of  the  precentral  fissure  of  the  frontal  lobe  into  the  longitudinal  fissure. 

The  Occipital  Lobe  forms  the  posterior  extremity  of  the  hemisphere  of  the 
cerebrum,  and  is  next  to  the  smallest  of  the  five  divisions  of  the  hemisphere  of 
the  cerebrum — the  island  of  Reil  being  still  smaller.  It  is  triangular  in  shape, 
with  its  base  directed  forward  and  its  apex  backward  ;  it  fills  the  superior  fossa  of 
the  occipital  bone,  and  rests  upon  the  tentorium  cerebelli.  It  presents  three  sur- 
faces :  a  lateral  or  convex,  an  inner  or  me-sial,  and  a  tentorial  or  basilar  surface. 
Owino-  to  the  absence  of  a  distinct  line  of  demarcation  the  lateral  surface  of  the 
occipital  lobe  is  continuous  with  the  corresponding  surface  of  the  parietal  and  tem- 
poro-sphenoid  lobes,  and  the  basilar  surface  of  this  lobe  with  the  corresponding 
surface  of  the  temporo-sphenoid  lobe.  The  inner  surface  of  the  occipital  lobe  is 
clearly  marked  off  from  the  corresponding  surface  of  the  parietal  lobe  by  the 
median  limlj  or  main  portion  of  the  jiarieto-occipital  fi.ssure.  A  line  drawn  from 
the  extremity  of  the  lateral  limb  of  the  parieto-occipital  fissure  over  the  external 
surface  of  the  hemisphere  to  the  preoccipital  notch,  and  continued  acro.ss  the 
basilar  surface  to  meet  the  end  of  the  median  limb  of  this  fissure,  will  i^ractically 
mark  off  the  anterior  limit  of  this  lobe  upon  these  two  surfaces. 

In  studying  the  convolutions  comprising  the  different  lobes  of  the  cerebrum, 
those  of  the  occipital  are  the  most  difficult  to  understand.  Upon  the  lateral  sur- 
face of  this  lobe  are  three  horizontal  fissures,  the  superior,  the  middle,  and  the 
inferior  occipital,  witli  sometimes  a  fourth  fissure,  vertical  in  direction,  and  known 
as  the  transverse  occipital  fissure.  The  transverse  and  the  superior  occipital 
fissure,  the  least  variable  of  the  four  fissures,  are  the  most  important  in  tracing 
the  convolutions  of  this  surface. 

The  transverse  occipital  fissure,  into  whicli  the  intra-parietal  frequently 
opens,  runs  over  the  lateral  surface  of  the  lobe  a  short  distance  behind  the  terminal 
portion  nf  tlic  lateral  limb  of  the  parieto-occipital  fissure. 

Tlic  superior  occipital  fissure  runs  from  before  backward  as  though  it  were  a 
continuation  of  the  Imiiznntal  liml)  of  the  intra-parietal  fissure. 

The  middle  occipital  fissure  is  seldom  well  developed,  and  extends  from 
before  backward. 

Tlir  inferior  occipital  fissure  is  frequently  intorrnpte<l  liy  bridging  convolu- 
tions, and  runs  from  lictnre  backward  along  the  line  of  junction  of  the  lateral  and 
basilar  surfaces  of  the  lol)e. 

(V)xv()i,rTiONS. — Through  the  medium  df  the  superior,  middle,  and  inferior 
occipital  lissurc's  the  lateral  surface  of  the  occi|iital  lobe  is  divided  into  the  superior 
or  first,  the  middle  or  second,  and  the  inferior  or  third  oeciiiital  convolution. 


rilE   CEREBRUM.  -JUl 

Tilt.'  superior  occipital  convolution  lies  l>(,'twrrii  tlio  Idii.nitudinal  ami  su|ii_rinr 
occipital  fissures,  and  (■oiiiiiu'iu-cs  at  IIk,'  postcriur  end  of  llie  siiperiur  jiaiiital 
convolution,  to  wliicli  it  is  eonuectcd  hy  the  lirst  unnectant  gyrus.  It  then  winds 
around  the  extremity  of  tlie  lateral  liniK  of  the  parieto-oceipitul  and  tlie  mesial 
end  of  the  transverse  occipital  fissure,  wluu  present,  and  becomes  continuous  with 
the  euneus,  a  wcdg-e-shaped  lobule  seen  upon  the  inner  surface  of  the  lobe. 

The  middle  occipital  convolution  lies  between  the  superior  and  middle 
occipital  fissures,  and  eonnnt'uees  at  the  outer  side  of  the  intra-parictal  fissure,  and 
behind  the  angular  gyrus,  ti>  which  it  is  et)nnected  l)y  the  second  and  tliinl 
annectant  gyri. 

The  inferior  occipital  convolution  lies  between  the  middle  and  inferior  occipi- 
tal fissures,  and  is  connected  to  the  inferior  or  third  temporo-sphenoid  convolution 
by  the  fourth  annectant  gyrus. 

Upon  the  inner  surface  of  the  occipital  lobe  there  is  but  one  secondary 
fissure,  the  calcarine,  and  one  lobule,  the  euneus. 

The  calcarine  fissure  commences,  usually,  by  two  branches  close  to  the  lower 
border  of  the  posterior  extremity  of  tlie  hemisphere  of  the  cerebrum,  runs  almost 
horizontally  forward  along  the  margin  formed  by  the  median  and  basilar  surfaces 
of  the  hemisphere,  and  joins  the  parieto-occipital  fissure  at  an  acute  angle 
behind  and  below  the  posterior  extremity  of  the  corpus  callosum.  Tliis  fissure 
gives  rise  to  a  prominence,  the  calcar  avis  or  hippocampus  minor,  seen  in  the 
posterior  horn  of  tlie  lateral  ventricle. 

The  euneus  is  a  triangular  lobule  situated  between  the  median  limb  or 
main  portion  of  the  parieto-occipital  fissure  and  the  calcarine  fissure.  Its 
base  is  directed  upward  and  Itackward,  and  is  formed  by  the  inner  border  of 
the  superior  occipital  convolution  ;  its  apex  is  directed  downward  and  forward, 
and  corresponds  to  the  angle  of  union  of  the  calcarine  and  parieto-occipital 
fissures. 

The  fissures  and  convolutions  of  the  basilar  surface  of  the  occipital  lobe  are 
uninterruptedly  continuous  with  those  of  the  corresponding  surface  of  the  temporo- 
sphenoid  lobe,  and  therefore  the  inferior  surface  of  these  two  lobes  will  }><•  studied 
as  the  lower  occipito-temiroral  surface. 

The  Temporal  or  Temporo-sphenoid  Lobe  is  that  part  of  the  hemisphere  of 
the  cerebrum  which  extends  into  the  middle  cranial  fossa,  its  po.sterior  portion 
resting  upon  the  tentorium  cerebelli.  It  lies  liehind  the  commencement  of  the 
basilar  or  main  portion  of  the  fissure  of  Sylvius,  in  front  of  a  line  drawn  over 
the  lateral  surface  of  the  hemisphere  of  the  cerebrum  from  the  extremity  of  the 
lateral  limb  of  the  parieto-occipital  fissure  to  the  preoccipital  notch,  and  below  the 
horizontal  limb  of  the  fissure  of  Sylvius  and  a  line  representing  its  continuation 


492  SURGICAL  ANATOMY. 

backward.     The  posterior  portion  of  this  lobe  is  continuous  with  the  parietal  and 
occipital  lobes,  as  mentioned  under  the  description  of  those  lobes. 

Surfaces. — The  teniporo-sphenoid  lobe  presents  an  external,  lateral  or  convex 
and  an  inferior  or  basilar  surface.  In  addition  some  anatomists  describe  an 
upper  or  Sylvian  surlace  in  relation  with  the  horizontal  lindi  of  the  fissure  of 
Sylvius.  Upon  the  lateral  surface  are  three  secondary  fissures  which  run  horizon- 
tally :  the  superior  temporo-sphenoid  or  parallel  fissure,  the  middle  tem])oro- 
sphenoid,  and  the  inferior  temporo-sphenoid  fissure.  Of  these  fissures,  the  supe- 
rior temporo-sphenoid  or  parallel  is  the  most  constant,  and  lies  entirely  on  the 
lateral  surface,  while  the  middle  and  the  inferior  are  mucli  more  varial)le.  They 
are  seldom  developed  with  equal  clearness,  and  are  frequently  interrupted  and 
bridged  by  convolutions.  The  middle  temporo-sphenoid  fissure  lies  almost  entirely 
on  the  lateral  surface,  while  the  greater  part  of  the  inferior  temjioso-sphcnoid 
fissure  is  on  the  liasilar  surface. 

The  superior  temporo-sphenoid  or  parallel  fissure  commences  near  the  ante- 
rior extremity  or  apex  of  the  lobe.  It  then  runs  backward  and  upward,  parallel 
with  the  horizontal  limb  of  the  fissure  of  Sylvius, — hence  the  name  of  parallel 
fissure, — and  terminates  in  the  inferior  parietal  convolution,  its  posterior  extremity 
being  surrottnded  by  the  angular  convolution. 

The  middle  temporo-sphenoid  fissure  commences  on  the  basilar  surface  of  the 
lobe,  and  runs  upward  and  backward,  parallel  with  the  superior  temporo-sphenoid 
fissure.  It  terminates  in  the  inferior  parietal  conlution,  its  posterior  extremity 
being  surrounded  l)y  the  post-parietal  convolution. 

The  inferior  temporo-sphenoid  fissure  lies  in  great  part  on  the  basilar  sur- 
face, near  the  margin  of  the  hemisphere,  and  terminates  posteriorly  on  the  lateral 
surface ;  it  separates  the  inferior  temporo-sphenoid  convolution  from  the  lateral 
occipito-temporal  convolution  or  fusiform  lobule. 

Convolutions. — Through  the  medium  of  the  superior,  middle,  and  inferior 
temporo-sphenoid  fissures  the  lateral  surface  of  the  temporo-sphenoid  lobe  is  div- 
ided into  three  convolutions  :  the  superior  temporo-sphenoid,  the  middle  temporo- 
sphenoid,  and  the  inferior  temporo-sphenoid  convolution. 

The  superior  temporo-sphenoid  or  infra-marginal  convolution  lies  between 
the  horizontal  limb  of  the  fissure  of  Sylvius  and  the  parallel  fissure  ;  it  is  continu- 
ous at  its  posterior  part  with  the  supra-marginal  and  angular  convolutions. 

The  middle  temporo-sphenoid  convolution  lies  between  the  jiarallel  fissure 
and  the  middle  temporo-.sphenoid  fissure,  being  clearly  marked  otf  above  bj'  the 
parallel  fissure.  Its  lower  boundary  is  by  no  means  so  coniBtantly  well  marked, 
and  it  is  frequently  continuous  with  tlie  inferior  temporo-sphenoid  convolution. 
It  is  continuous  posteridrly  with  the  angular  convolution. 


PLATE  CXXI, 


Collateral  fissure 
Fusiform  lobule 
Uncus 


inferior  temporosphenoid  fissure 

Superior  temporo-sphenoid  fissure 


Hippocampal  fissure 
Hiopocampal 

convolution 

Optic  commissure 
Crus  cerebri 


Isthmus 


Parieto-occipital 

fissure 


Lingual  lobule 

Cuneus —   - 

Calcarine  fissure- 


Superior  temporo-sphenoid  gyrus 
ddle  temporo-sphenoid  gyrus 
Middle  temporo-sphenoid  fissure 
Inferior  temporo-sphenoid  gyrus 


INFERIOR  SURFACE  OF  OCCIPITAL  AND  TEMPORAL  LOBES. 
4S)4 


THE   CEREliinM.  495 

Tlu>  inferior  temporo-sphenoid  convolution  lies  along  llir  lnt(i:il  luaruin  df  tlie 
Iii'inisiilK'n',  lu'twi'i'ii  the  miilillc  tcinporo-i^plienoid  fissure  and  the  iiiferidr  U'liqioro- 
sphenoitl  lissure ;  it  passes  above  tlie  preoceipital  notcli,  and  is  continuous  beliind 
witli  the  third  occipital  convolution.  Upon  the  basilar  surface  of  the  lobe  it  is 
continuous  with  the  external  occipito-temporal  convolvition,  or  fusiform  lobule. 

The  upper  or  Sylvian  surface  of  the  temporo-sphenoid  lobe  is  in  contact  with 
the  operculum,  and  intimately  related  to  the  island  of  Reil ;  it  ])res('nts  two  oi-  tlu'ee 
transverse  convolutions. 

The  fissures  and  convolutions  presenting  on  the  basilar  surface  being  continu- 
ous with  those  of  the  occipital  lobe,  they  will  be  described  as  part  of  the  lower 
occipito-temporal  surface. 

Collateral  fissure. — The  basilar  surface  of  the  temporo-sphenoid  lol)e  contains 
the  greater  portion  of  the  inferior  temporo-sphenoid  fissure,  as  previously  described. 
That  portion  of  this  sui'face  which  is  coi'itinuous  with  the  occipital  lobe,  and 
designated  as  the  lower  occipito-temporal  surface,  presents  a  constant  and  impor- 
tant secondary  fissure,  the  inferior  occipito-temporal  or  collateral  fissure.  This 
commences  at  the  posterior  extremity  of  the  oecijiital  lobe  ;  thence  it  runs  forward 
j>arallel  to  and  boluw  the  calcarine  fissure,  nearly  to  the  apex  of  the  temporo- 
sphenoid  lobe,  extending  almost  as  far  as  the  commencement  of  the  Sylvian 
fissure.  It  is  sometimes  bridged  over  by  a  secondary  convolution.  It  produces 
the  eminentia  collateralis,  a  prominence  in  the  floor  of  the  descending  cornu  of 
the  lateral  ventricle,  seen  at  the  point  of  divergence  of  the  middle  and  posterior 
cornua  of  the  A^entricle.  Through  the  medium  of  the  collateral  and  hiiiiiocampal 
fissures  the  lower  occipito-temporal  .surface  is  divided  into  three  convolutions :  the 
fusiform  lo))ule,  the  lingual  lolmle,  and  tlu'  hippocampal  or  uncinate  convolution. 
The  hippocampal  convolution  and  the  lingual  kiljule  are  Imt  portions  of  the 
internal  or  mesial  occipito-temporal  convolution. 

The  lingual  lobule  lies  between  the  collateral  fissure  on  the  outer  side,  and 
the  calcarine  fissure  on  the  inner  side.  It  occupies  chiefly  the  occipital  part  of  the 
lower  oceii>ito-temporal  surface.     It  is  wide  behiml  and  narrow  in  front. 

Till'  hippocampal  or  uncinate  convolution  lies  between  the  collateral  fissure 
on  the  outer  side  and  the  hippocampal  on  the  inner  side.  It  is  formed  by  the 
union  of  the  isthmus  or  posterior  continuation  of  the  gyrus  fornicatus  with  the 
lingual  lobule  at  the  anterior  extremity  of  the  mesial  limb  of  the  parieto-occipital 
fissure.  It  continues  forwanl,  ))ordering  the  hippocampal  fissure  and  embracing 
the  crura  cerebri,  to  terminate  innnediately  behind  the  anterior  perforated  space 
by  turning  upward  and  backward  upon  itself  in  the  uncvs. 

The  external  or  lateral  occipito-temporal  convolution,  or  fusiform  lobule, 
lies  between  the  collateral   fissure  on    the  inner  side,  and  the  inferior  temporo- 


496  SURGICAL  ANATOMY. 

sphenoid  fissure,  when  present,  on  the  outer  side.  When  the  inferior  temporo- 
sphenoid  fissure  is  wanting  or  is  incomplete,  the  lateral  boundary  of  this  convolu- 
tion is  indistinct.  It  extends  from  the  apex  of  the  temporo-sphenoid  lobe  to  the 
posterior  extremity  of  the  occipital  lobe. 

The  hippocampal  or  dentate  fissure,  i)rcviously  mentioned  as  being  bordered 
by  the  hippocampal  convolution,  correspontls  to  the  lateral  portion  of  the  tran.s- 
verse  fissure  of  Bichat.  It  is  situated  in  front  of  the  calcarine  fissure,  between  the 
crura  cerebri  and  the  hippocampal  convolution,  and  extends  outward,  downward, 
and  forward  from  the  splenium  of  the  corpus  callosum  to  the  uncus.  It  produces 
the  cornu  Ammonis  or  hippocampus  major,  a  }ironnnence  forming  part  of  the 
inner  wall  of  the  middle  cornu  of  the  lateral  ventricle.  By  drawing  the  hippo- 
campal convolution  away  from  the  crus  cereljri,  thus  widening  the  hippocampal 
fissure,  there  will  be  seen  a  band  of  gray  matter  which  reaches  from  the  splenium 
of  the  corpus  callosum  to  tlie  uncus.  This  is  the  free  edge  of  the  hippocampal 
convolution,  and  its  notched  appearance  is  produced  by  the  clioroid  arteries,  which 
pass  through  the  fissure  with  the  pia  mater  into  the  descending  horn  of  the  lateral 
ventricle ;  this  gray  matter  is  known  as  the  fascia  dcntata,  or  the  dentate 
convolution. 

The  remaining  fissures  seen  on  the  inner  surface  of  the  hemisphere  of  the 
cerebrum  are  the  calloso-marginal  and  the  callosal  fissure,  and  the  remaining 
convolution  is  the  gyrus  fornicatus. 

The  calloso-marginal  fissure,  the  terminal  portion  of  which  was  mentioned 
when  describing  the  location,  of  the  fissure  of  Rolando,  connnences  below  the 
rostrum  of  the  corpus  callosum,  curves  forward  around  the  genu,  and  backward 
above  the  body  of  the  corpus  callosum.  It  runs  about  midwav  between  tlie 
corpus  callosum  and  the  u]iper  border  of  the  hemisphere  to  a  point  opposite  the 
splenium  of  the  corpus  callosum,  where  it  turns  ui)\vard  and  slightly  backward  to 
terminate  on  the  upper  border  of  the  hemisphere  of  the  cerebrum,  immediately 
behind  the  connnencement  of  the  fissure  of  Rolando.  From  the  point  where  the 
fissure  turns  u})ward  to  reach  the  margin  of  the  hemisphere  thei'e  is  fret|uently 
found,  following  the  original  direction  of  the  calloso-marginal,  a  small  fissure 
which  separates  the  quadrate  lobule  from  the  gyrus  fornicatus.  This,  under  the 
name  of  the  subparietal  fissure,  is  a  liranch  of  the  calloso-marginal,  as  is  also  the 
paracentral  fissure.  The  calloso-marginal  fissure  is  not  infre(|ueiitly  bridged  over 
in  places  by  secondary  convolutions  which  connect  the  marginal  gyrus  with  the 
gyrus  fornicatus. 

The  callosal  fissure,  or  ventricle  of  the  corpus  cailostnn,  connnences  below 
the  rostrum,  follow.s  the  superior  surface  of  the  corpus  callosum,  and  terminates 
l)chind  the  sjilcnium  of  the  corpus  callosum  in  the  hippocampal  fissure. 


PLATE  CXXll. 


Paracentral  lobule. 
Tegmentum  of  crus  cerebri 
Paracentral  fissure 
Fornix 
Calloso-marginal  fissure 

Fifth  ventricle 
Gyrus  fornicatus 
Genu  of  corpus  callosum 
Marginal  convolution 


Locus  niger 

,Crusta  of  crus  cerebri 
Velum  intetpositum 
allosal  fissure 

Splenium  of  corpus  callosum 
Sub-parietal  fissure 
Quadrate  lobule 

CuneuS' 


Internal  orbital  gyrus 
Anterior  orbital  gyrus 

Triradiate  fissure' 
Posterior  orbital  gyrus 


Calcarine  fissure 
Lingual  lobule 
Parieto-occipital  fissure 
Collateral  fissure 
Isthmus 
Fusiform  lobule 
inferior  temporo-sphenoid  ficsure 
Hippocampal  fissure 
Hippocampal  convolution 


Gyrus  rectu 
Olfactory  sulcus' 
Rostrum  of  corpus  callosum 


Uncus 
Optic  thalamus 
Lateral  ventricle 


11—3-2 


MEDIAN  AND  INFERIOR  SURFACES  OF  CEREBRUM. 
497 


CRAMO-VKREBHAL    TOPOGRAPHY.  499 

The  gyrus  fornicatus  lies  between  the  calloso-raarginal  fissure  ami  the  eallo- 
sal  fissure.  It  commences  in  trout  of  the  anterior  perforated  space,  between  tlie 
rostrum  of  the  corpus  callosuni  and  the  marginal  convolution,  follows  the  super- 
ficial surface  of  the  corpus  callosuni,  and  terminates  below  the  splenium  of  the 
corpus  callosum  in  a  narrow  extremity,  the  isthmus,  which  joins  the  hippocampal 
convdlution. 

The  Limbic  Lobe  includes  a  munber  of  convolutions  arranged  in  a  ring-like 
manner ;  some  of  the  parts  are  quite  rudimentary  in  the  human  brain,  and  are  the 
lepresentatives  of  more  highly  developed  structures  in  some  of  the  lower  animals. 
The  limbic  lobe  is  made  up  of  the  gyrus  fornicatus,  hippocampal  gyrus,  the  rudi- 
mentary gyrus  supra-callosus  of  Zuckerkandl  (formed  by  the  peduncles  of  the 
corpus  callosum,  fascia  dentata,  and  the  longitudinal  strice  on  the  upper  surface  of 
the  corpus  callosum),  together  with  half  of  the  fornix  and  the  corresponding 
lamina  of  the  septum  lucidum.  This  lobe  is  bounded  bv  the  calloso-marginal  and 
collateral  fissures,  and  each  extremity  of  it  is  continuous  with  one  of  the  roots  of 
the  olfoctory  tract. 

CRANIO-CEREBRAL  TOPOGRAPHY. 

Sensory  and  Motor  Areas. — Having  completed  the  study  of  the  fissures,  the 
lobes,  and  the  convolutions  of  the  hemisphere  of  the  cerebrum,  consider  the  func- 
tions of  the  convolutions  in  certain  areas  of  the  surfaces  of  the  cerebrum  before 
commencing  the  dissection  of  that  part  of  the  l)rain.  The  two  principal  regions 
of  the  hemisphere  are  the  motor  area  and  the  sensory  area.  The  motor  area  com- 
prises the  posterior  ends  of  the  superior,  middle,  and  inferior  frontal  convolutions, 
the  ascending  frontal  convolution,  the  ascending  parietal  convolution,  and  the 
adjoining  part  of  the  superior  parietal  convolution.  The  sensory  area  of  the 
surfiice  of  the  cerebrum  has  been  imperfectly  outlined  on  account  of  the  greater 
difficulty  attending  its  localization. 

The  Silent  Region. — The  anterior  two-thirds  of  the  superior,  middle,  and 
inferior  frontal  convolutions,  or  that  portion  of  the  frontal  lobe  which  practically 
lies  in  advance  of  the  coronal  suture  with  the  brain  in  its  natural  position,  is  the 
prefrontal  or  silent  region  of  the  brain,  where,  if  a  lesion  be  present,  it  does  not  give 
rise  to  any  localizing  symptoms.  The  author  has  frequently  seen  the  prefrontal 
region  severely  injured  in  gunshot  wounds  with  entire  absence  of  any  paralytic 
symptoms.  He  has  also  seen  cases  of  abscess  of  this  region  with  similar  absence  of 
any  localizing  symptoms.  One  case  in  particular  in  his  experience  was  that  of  a 
large  abscess  of  the  left  prefrontal  region,  which  followed  a  punctured  fracture 
of  the  cril)riform  plate  of  the  ethmoid  bone.  The  patient  was  a  boy,  M'ho,  while 
playing  with  a  hoisted  umbrella,  threw  it  up  in  the  air.     In  its  descent  it  turned, 


500  SURGICAL  ANATOMY. 

and  a  portion  of  one  of  the  ribs  passed  into  his  left  nostril  and  penetrated  the 
cranial  cavity,  fracturing  the  cribriform  plate  of  the  ethmoid  bone,  tearing  through 
the  dura  mater,  and  finally  entering  the  frontal  lobe.  A  brain  abscess  developed 
— so  considered  at  the  time  and  afterward  proved  Ity  autopsy.  The  collection 
occupied  the  left  prefrontal  lobe,  and  at  no  time  in  the  course  of  the  disease  were 
there  any  localizing  symptoms.  The  function  over  which  this  region  of  the  Vjrain 
is  believed  to  preside  is  that  of  the  higher  mental  faculties,  and  in  di.sease  or 
injury  of  this  region,  particularly  upon  the  left  side,  there  is  very  apt  to  be  more 
or  less  hebetude,  dullness  of  intellect,  and  lack  of  self-control. 

Motor  Centers. — The  motor  area  embraces  the  centers  which  preside  over  the 
movements  of  the  opposite  side  of  the  body,  and  is  conveniently  divided  into 
thirds — an  upper,  a  middle,  and  a  lower.  The  upper  third  includes  the  centers 
which  control  the  movements  of  the  muscles  of  the  lower  extremity ;  the  middle 
third,  the  centers  which  control  the  movements  of  the  muscles  of  the  upper 
extremity  ;  and  the  lower  third,  the  centers  which  control  the  movements  of  the 
muscles  of  the  face,  the  mouth,  and  the  tongue.  It  would  seem  from  recent 
investigation  tliat  the  centers  for  tactile  sensation  are  located  in  the  same  area  as 
that  occupied  by  the  motor  centers,  for  some  loss  of  tactile  sense  may  accompany 
motor  paralysis  ;  hence  the  centers  about  to  be  described  are  at  times  referred  to 
as  the  sensori-motor  areas.  There  is  some  evidence  in  favor  of  locating  the  centers 
for  muscular  sense  in  the  region  just  posterior  to  the  motor  area,  in  the  neighbor- 
hood of  the  great  longitudinal  fissure.  The  following  is  a  detailed  description  of 
the  location  of  the  individual  centers  of  the  motor  and  sensory  areas  (Ferrier) : 
The  centers  which  control  the  movements  of  the  opposite  leg  and  foot,  such  as  are 
concerned,  for  example,  in  walking,  are  situated  in  the  anterior  part  of  the  supe- 
rior parietal  convolution,  at  its  junction  with  the  ascending  parietal,  in  the 
paracentral  lobule  and  part  of  the  quadrate  lobule.  The  upper  part  of  the 
ascending  frontal  convolution  with  the  neighboring  part  of  the  base  of  the  superior 
frontal  convolution  include  the  centers  which  control  the  various  complex  move- 
ments of  the  arms  and  legs,  such  as  climbing,  swimming,  etc.  The  posterior  third 
of  the  superior  frontal  convolution  anterior  to  the  junction  of  its  base  with  the 
ascending  frontal  includes  the  centers  for  the  forward  extension  of  the  arm  and 
hand,  as  in  reaching  forth  the  hand  to  touch  something  in  front.  The  upper  part 
of  the  middle  third  of  the  ascending  frontal  convolution  includes  the  centers  for 
those  movements  of  the  hand  and  forearm  which  call  into  action  the  biceps,  as 
supination  of  the  hand  and  flexion  of  the  forearm.  The  ascending  frontal 
convolution,  at  aliout  the  junction  of  its  middle  and  lower  thirds,  includes  the 
centers  wiiich  control  the  action  of  the  elevators  and  depressors  of  the  angle  of 
the  mouth. 


PLATE  CXXlll, 


Centers  for  (i)  Opposite  leg  and  foot,  as  m  walking  (2)  Arms  and  legs,  as  in  clinnbing  or  swimming.  (3)  Forward  extension  of  arm 
and  hand.  (4)  Supination  of  hand  and  flexion  of  forearm.  {5)  Elevators  and  depressors  of  angle  of  mouth.  (6)  Lips 
and  tongue  In  talking  {7)  Platysma  myoides  muscle.  (8)  Lateral  movement  of  head  and  eyes,  elevation  of  eyelids,  and 
dilatation   of  pupil.      (9)    Movement   of  fingers   and   wrist.      (10)   Vision.      (11)   Hearing. 


MOTOR  ANO  SENSORY  AREAS  OF  CEREBRUM  (AFTER  FERRIER). 
501 


ii 


CRAMo-cEiiKiii:. I /,  'mp()<;i;. inn:  503 

The  base  of  the  third  frontal  convohition  ami,  to  a  slight  (Icgrw,  tlir  Iciwii- 
011(1  of  tlie  ascending  frontal  and  asa'nding  parii'lal  convolutions  include  the 
centers  for  the  movements  of  the  lips  and  tongue  in  talking.  This  region  is 
known  as  Bwca's  region,  disease  of  which  on  the  left  side  causes  aphasia,  or  loss  of 
the  power  of  speech.  The  speech  center,  however,  is  not  always  in  the  left  side  of 
the  brain.  In  leftdianded  persons  it  is  located,  as  has  been  demonstrated  clini- 
cally, in  the  base  of  the  right  third  frontal  convolution. 

Aphasia  is  of  two  varieties,  the  motor  or  ataxic,  and  the  sensory  or  amnesic. 
In  the  motor  variety  there  is  inability  to  pro|)erly  coordinate  the  muscles  presiding 
over  articulation,  while  in  the  sensory  variety  there  is  loss  of  memory  for  words. 
The  .speech  center  is  connected  with  the  centers  of  hearing  and  vision  through  llu; 
medium  of  the  associating  fibers  of  the  cerebrum,  and  also,  through  the  medium 
of  the  speech  tract,  with  the  centers  in  the  medulla  oblongata  which  give  origin 
to  the  nerves  which  are  employed  in  speech.  Oidy  through  this  connection 
between  the  speech  center,  the  centers  of  hearing,  and  the  centers  of  vision  can 
the  two  forms  of  sensory  aphasia — namely,  word-deafness  and  word-blindness — 
be  understood.  The  ability  to  write  is,  as  a  rule,  lost  in  cases  of  destruction  of 
the  motor  area  for  speech. 

The  lower  third  of  the  ascending  parietal  convolution,  at  its  junction  with  the 
inferior  parietal,  includes  the  center  which  controls  the  movements  of  the  platysma 
myoides  muscle  in  bringing  about  retraction  of  the  angle  of  the  mouth.  The  base 
of  the  middle  frontal  convolution  includes  the  center  for  lateral  movements  of  the 
head  and  eyes,  with  elevation  of  the  ej-elids  and  dilatation  of  the  pupil.  The 
middle  third  of  the  ascending  parietal  convolution  includes  the  centers  for  the 
movements  of  the  fingers  and  wrist. 

The  cortical  centers  for  the  different  muscles  and  limbs  overlap  to  a  certain 
extent,  so  that  while  there  is  a  more  or  less  distinct  focus  of  representation  for  a 
given  set  of  muscles,  adjacent  parts  of  the  cortex  are  also  concerned  in  governing 
the  muscles  presided  over  by  the  focus ;  hence  total  paralysis  does  not  necessarily 
follow  removal  of  a  limited  area  of  the  cortex  of  the  cerebrum. 

The  supra-marginal  and  angular  convolutions,  in  addition  to  the  occipital 
lobe,  include  the  centers  of  vision ;  these,  taken  together,  have  been  termed  by 
Ferrier  the  occipito-angular  region.  The  posterior  part  of  the  superior  temporo- 
sphenoid  convolution  includes  the  centers  of  hearing.  The  anterior  extremitj'  of 
tlie  hippocampal  convolution  or  uncus  includes  the  center  of  smell,  while  in  close 
proximity  to  the  center  of  smell  is  the  center  of  taste.  The  convolution  of  tht? 
corpus  callosum  and  the  posterior  part  of  the  hippocampal  convolution  include 
the  center  of  touch. 

Each  occipital  lobe  receives  visual  impulses  from  one-half  of  both  retinae,  so 


504  SURGICAL  ANATOMY. 

that  a  unilateral  cerebral  lesion  may  produce  what  is  known  as  licmianopnia,  a 
symmetric  defect  in  the  field  of  vision  of  the  two  eyes. 

Disease  of  the  Cortex  of  the  Cerebrum. — Irritation  of  the  motor  area,  as  by  a 
small  meningeal  hemorrhage,  meningitis,  or  the  application  of  a  weak  Faradic 
current,  causes  twitching  or  convulsive  movements  of  the  muscles  of  the  oj)posite 
side.  When  the  motor  area  is  destroyed  by  disease  or  injury,  there  is  complete 
paralysis  of  motion  of  the  opposite  side.  If  both  the  motor  and  the  sensory 
areas  are  involved  in  the  jiathologic  process,  both  sensation  and  motion  of  the 
ojjposite  side  will  be  affected.  In  trephining  for  focal,  or  Jacksonian,  epilepsj^  it 
is  customary  when  the  brain  cortex  lias  been  exposed  to  appl}'  a  weak  Faradic 
current  to  that  portion  believed  to  include  the  centers  wliich  are  concerned  in 
the  initial  convulsive  seizure  ;  in  other  words,  the  convulsive  movements  which 
the  patient  exhibited  during  the  attacks  are  reproduced  by  the  application  of 
the  current.  In  this  manner  the  different  centers  presiding  over  the  various 
movements  of  the  opposite  side  can  be  located.  "\Mien  the  affected  centers  have 
been  definitely  located,  the  entire  thickness  of  the  gray  matter  in  the  affected 
area  is  excised.  This  naturally  results  in  })aralysis  of  the  parts  over  whose 
motion  they  have  heretofore  presided.  The  arrest  of  any  bleeding  and  closing  and 
dressing  the  wound  complete  the  operation.  It  is  hardly  necessary  to  say  that 
if  a  lesion  such  as  an  enlarged  Pacchionian  bod)-,  a  cyst,  a  cicatrix,  or  a  neoplasm 
is  found,  it  should  be  excised.  This  operation  demonstrates,  therefore,  the  effect 
of  both  irritation  and  destruction  of  the  motor  area.  In  following  up  the  cases 
of  Jacksonian  epilepsy  treated  by  operation,  it  is  interesting  to  note  that  the 
paralysis  which  follows  the  excision  of  the  cortex  diminishes,  after  a  time,  to 
such  an  extent  as  to  permit  of  a  return  of  the  convulsions.  The.se  operations, 
therefore,  afford  but  temporary  relief  in  the  great  majority  of  cases.  The  return 
of  function  occurs  through  the  compensatory  action  of  the  neighboring  cells. 

Abolition  of  the  function  of  certain  groups  of  centers  in  the  motor  area  of  the 
cortex  cerebri  results  in  one  or  other  of  the  following  varieties  of  paralysis  :  If  of 
the  arm  and  leg,  it  is  called  brachio-crui'al  paralysis,  or  hemiplegia  ;  if  of  the  leg 
alone,  crural  monoplegia  ;  if  of  the  arm  alone,  brachial  monoplegia ;  and  if  of 
the  face  alone,  facial  monoplegia.  Facial  monoplegia  seldom  occurs  alone,  and  is 
most  commonly  associated  with  aphasia,  owing  to  the  close  proximity  of  the  facial 
and  speech  centers. 

The  centers  of  hearing,  vision,  smell,  and  taste  may  be  irritated  by  various 
lesion.s,  so  that  hallucinations  of  these  senses  may,  like  motor  disturbances,  arise 
from  irritation  of  the  motor  cortex.  Thus,  the  so-called  sensory  equivalent  of  a 
Jacksonian  convulsion  is  produced,  and  from  the  character  of  this  attack  deduc- 
tions as  to  the  location  of  the  lesion  may  be  drawn. 


PLATE  CXXIV. 


Breg 


LINES  FOR  FISSURES,  LOWER   LEVEL  OF  CEREBRUM. 
506 


CRAXIO-fEREBUM.    Tol'Od h'A I'lIY.  507 

DissKCTiON. — Shave  the  scalp  uiion  one  side  of  the  lu-ad,  and  uiiuii  the  other, 
turn  its  entire  thickness  down  in  one  Hap.  Uj)on  tliat  side  where  the  skull  wall  is 
exposed  remove  half  of  the  calvaria  with  a  saw  or  a  cliisel  and  mallet.  Next 
reflect  the  dura  mater  in  one  tiap  and  dissect  off'  tlie  araclnioid  and  pia  mater  to 
expose  the  fissures  and  convolutions. 

A  familiarity  with  certain  of  the  cranial  lamlmai-ks  is  essential  in  the  study 
of  cranio-cerebral  topography.  These  include  the  glal)ella  (a  point  between  the 
eyebrows),  the  frontal  eminence,  the  external  angular  process  of  the  frontal  bone, 
the  zygomatic  arch,  the  preauricular  fossa  (tlie  depression  in  front  of  the  tragus  on 
a  level  with  the  upper  border  of  the  external  auditory  meatu.s),  the  external 
auditory  meatus,  the  mastoid  process,  the  parietal  eminence,  and  the  external 
occipital  jirotuberance  or  iniou. 

The  Lower  Level  of  the  Cerebrum. — A  line  drawn  horizontally  across  the 
forehead  through  the  upper  part  of  the  glabella  approximately  corresponds  to  the 
lower  level  of  the  cerebrum  in  front.  A  line  drawn  from  the  external  angular 
process  of  the  frontal  bone  through  the  preatiricular  fossa  to  the  external  occipital 
protuberance  approximately  corresponds  to  the  lower  level  of  the  cerebrum  at  the 
sides  and  behind.  The  cerebellum  lies  below  that  portion  of  the  last-mentioned 
line  included  between  the  posterior  border  of  the  mastoid  process  and  the  inion. 

Longitudinal  and  Transverse  Fissures. — A  line  drawn  from  the  glabella  over 
the  vertex  and  along  the  median  line  to  the  inion  corresponds  to  the  jiosition  of 
the  longitudinal  fissure.  A  line  drawn  from  the  inion  along  the  superior  curved 
line  of  the  occipital  bone  to  a  point  an  inch,  or  2.5  centimeters,  above  the  external 
auditory  meatus  corresponds  to  the  position  of  the  transverse  fissure. 

Fissure  of  Sylvius. — To  indicate  the  position  of  the  fissure  of  Sylvius,  draw 
a  line  from  a  point  one  and  one-fourth  inches,  or  three  centimeters,  behind  the 
external  angular  process  of  the  frontal  bone  to  a  point  three-fourths  of  an  inch,  or 
two  centimeters,  below  the  most  prominent  part  of  the  parietal  eminence.  The 
first  three-fourths  of  an  inch,  or  two  centimeters,  of  the  line  represent  the  main 
fissure  ;  and  the  remainder  of  the  line,  the  horizontal  lind>  of  the  fissure.  The 
a.scending  limb  of  the  fissure  is  represented  by  drawing  a  line  one  inch,  or  2.5 
centimeters,  in  length  vertically  upward  from  the  point  of  termination  of  the  main 
fissure — that  is,  three-fourths  of  an  inch,  or  two  centimeters,  from  its  commence- 
ment, or  five  centimeters  behind  the  external  angular  process  of  the  frontal  bone. 

Reid's  base  line  is  drawn  from  the  lower  border  of  the  orliit  thi-ough  the 
center  of  the  external  auditory  meatus.  This  line  is  of  assistance  in  locating  the 
fissure  of  Rolando. 

Fissure  of  Rolando. — To  represent  the  position  of  the  fi.ssure  of  Rolando, 
first  draw  two  perpendicular  lines  from  the  base  line  to  the  line  representing  the 


508  SURGICAL  ANATOMY. 

position  of  the  great  longitudinal  fissure.  The  anterior  of  these  passes  througli 
the  preauricular  fossa,  and  the  posterior  passes  along  the  posterior  border  of  the 
mastoid  process.  From  the  point  of  intersection  of  the  posterior  perpendicular  line 
with  that  of  tlie  great  longitudinal  fissure  to  the  point  of  intersection  of  tlie  ante- 
rior jjerpendicular  line  witli  that  of  the  liorizontal  linil)  of  the  fissure  of  Sylvius, 
draw  a  third  line,  which  represents  the  position  of  the  fissure  of  Rolando.  The 
fissure  of  Rolando  maj'  also  be  located  by  drawing  a  line  downward,  outward,  and 
forward  from  a  point  one-lialf  of  an  inch,  or  one  centimeter,  behind  a  point  mid- 
way between  the  glabella  and  inion  and  at  an  angle  of  71.5  degrees  with  the 
anterior  portion  of  the  line  for  the  longitudinal  fis.sure.  The  angle  formed  by  the 
fissure  of  Rolando  and  tlie  anterior  portion  of  the  longitudinal  fissure  varies,  but. 
in  any  instance,  the  line  for  the  fis.sure  is  merely  an  approximate  guide.  The 
fissure  measures  about  three  and  three-eighth  inches,  or  eight  and  one-half  centi- 
meters, in  length.  Upon  each  side  of  and  running  parallel  with  the  fissure  of 
Rolando  are  the  ascending  frontal  and  ascending  parietal  convolutions,  each  of 
which  occupies  a  space  about  three-fourths  of  an  incli,  or  two  centimeters,  in 
width. 

Parieto-occipital  fissure. — Extend  the  line  indicating  the  horizontal  limb  of 
the  fissure  of  iSylvius  backward  to  that  of  the  longitudinal  fis.sure,  and  the  lateral 
limb  of  the  parieto-occipital  fissure  will  be  represented  hy  about  the  posterior 
inch,  or  2.5  centimeters,  of  tins  line.  The  lateral  portion  of  the  parieto-occipital 
fissure  is  also  found  from  tlirce  to  three  and  one-half  inches,  or  eight  to  nine 
centimeters,  above  the  external  occipital  protuberance. 

Frontal  Lobe. — Through  the  medium  of  the  lines  indicating  the  course  of  the 
primary  fissures  of  the  hemisphere  the  lolies  are  mapped  out.  The  frontal  lobe 
lies  external  to  the  line  of  the  longitudinal  fi.s.sure,  in  front  of  the  line  of  the 
fissure  of  Rolando,  and  above  the  lines  for  tlie  lower  level  of  the  cerebrum  and  for 
the  main  and  horizontal  limbs  of  the  fissure  of  Sylvius.  The  course  of  the 
secondary  fissures  and  the  position  of  the  convolutions  of  this  lobe  will  be  repre- 
sented by  the  following  lines:  A  line  drawn  from  the  supra-orbital  notch  back- 
ward and  parallel  Avith  the  line  of  the  longitudinal  fissure  to  within  about  three- 
fourths  of  an  inch,  or  two  centimeters,  of  the  line  of  the  fissure  of  Rolando 
indicates  the  course  of  the  superior  frontal  sulcus.  A  line  drawn  from  the 
external  annular  process  of  tlie  frontal  lione  upward  and  l)ackward  along  the 
temporal  ridge  to  witliin  about  three-fourths  of  an  inch,  or  two  centimeters,  of  the 
line  of  the  fissure  of  Rolando  indicates  the  course  of  the  inferior  frontal  fissure. 
A  line  drawn  three-fourtii.s  of  an  inch,  or  two  centimeters,  in  front  of,  and  parallel 
with,  the  lower  two-thirds  of  the  line  of  the  fissure  of  Rolando  indicates,  approxi- 
mately, the  course  of  tlie  precentral  fissure.     The  .sujierior  frontal   convolution 


CRAXIO-CERKBRM.    TOPOGRAPHY.  509 

corresponds  to  the  intiTval  between  tlie  lines  of  tlic  loni^itudiiial  and  sniieiicir 
frontal  tissures.  The  middle  frontal  convolution  corresponds  to  tlie  intn-val 
between  the  lines  of  the  superior  and  inferior  frontal  fissures.  'i'iie  inferior 
frontal  convolution  corresponds  to  the  interval  between  the  line  of  tin-  inferior 
frontal  fissure  and  the  lines  representing  the  fissure  of  Sylvius  and  the  lower  level 
of  the  cerebrum  in  front.  The  ascending  frontal  convolution  corresponds  to  the 
interval  between  the  lines  of  the  fissure  of  Rolando  and  the   preeentral  lissure. 

The  Parietal  Lobe  lies  between  the  lines  of  the  longitudinal  fissure  and  the 
horizontal  lindi  of  the  lissure  of  Sylvius,  and  between  the  line  of  the  fissure  of 
Rolando  and  that  of  the  lateral  limb  of  the  parieto-occipital  fissure.  The 
boundary  between  the  parietal  and  occipital  lobes  is  indicated  aiiproximately  by  a 
line  drawn  from  the  lateral  lindj  of  the  parieto-occipital  fissure  to  the  posterior 
border  of  the  base  of  the  mastoid  process.  The  course  of  the  intra-parietal  fissure 
and  the  position  of  the  convolutions  of  the  parietal  lobe  are  represented  as  follows  : 
To  indicate  the  course  of  the  intra-parietal  fissure,  draw  from  a  point  one-half  of 
an  inch,  or  one  centimeter,  external  to  the  end  of  the  lateral  limb  of  the  parieto- 
occipital fissure  to  a  point  three-fourths  of  an  inch,  or  two  centimeters,  behind  the 
lower  end  of  the  fis.sure  of  Rolando,  a  line  which  is  convex  forward  ;  the  lower 
third  of  the  line  sliould  run  parallel  with  the  fi.ssure  of  Rolando.  The 
interval  bounded  by  this  line  and  the  lines  of  the  fissures  of  Rolando,  tlie  longi- 
tudinal fissure,  and  the  lateral  liml)  of  the  parieto-occipital  fi.ssure  will  correspond 
to  the  ascending  and  superior  parietal  convolutions.  The  ascending  parietal  con- 
volution runs  parallel  with  the  line  of  the  fis.sure  of  Rolando,  and  corresponds  to 
the  space  directly  behind  it  to  the  extent  of  three-fourths  of  an  inch,  or  two  centi- 
meters, while  the  remaining  portion  of  the  space  included  in  the  above  boundaries 
corresponds  to  the  superior  parietal  convolution.  The  inferior  parietal  convolu- 
tion, including  the  supra-marginal  and  angular  gyri,  corresponds  to  the  interval 
bounded  by  the  line  of  the  intra-parietal  fissure,  that  of  the  horizontal  limb  of  the 
fissure  of  Sylvius,  and  the  line  drawn  from  the  lateral  limb  of  the  parieto-occipital 
fissure  to  the  posterior  margin  of  the  base  of  the  mastoid  process.  The  supra- 
marginal  gyrus  lies  under  the  most  prominent  part  of  the  parietal  eminence. 

The  Occipital  Lobe  lies  behind  the  line  drawn  from  the  lateral  limb  of 
the  parieto-occipital  fissure  to  the  posterior  margin  of  the  base  of  the  mastoid 
process. 

The  Temporal  or  Temporo-sphenoid  Lobe  lies  below  the  line  of  the  horizontal 
limb  of  the  fissure  of  Sylvius  and  above  the  upper  border  of  the  zygoma,  and  a 
line  representing  the  continuation  of  the  latter  backward  to  a  point  slightly  above 
the  superior  curved  line  of  the  occipital  bone.     The  posterior  boundary  of  this  ^ 
lobe  corresponds  approximately  to  a  line  drawn  from  the  external  portion  of  the 


510  SURGICAL  ANAT03IY. 

parieto-occipital  fissure  to  the  posterior  limit  of  the  base  or  root  of  the  mastoid 
process.  This  lobe  in  front  reaches  as  far  as  the  posterior  superior  border  of  the 
malar  bone.  A  line  drawn  parallel  with  and  one  inch,  or  two  and  one-half  centi- 
meters, below  the  line  of  the  horizontal  limb  of  the  fissure  of  Sylvius  indicates  the 
course  of  the  superior  temporo-sphenoid  fissure.  A  line  drawn  parallel  with  and 
three-fourths  of  an  inch,  or  two  centimeters,  below  the  latter  line,  indicates  the 
course  of  the  middle  temporo-sphenoid  fissure.  The  superior  temporo-sphenoid 
convolution  corresponds  to  the  interval  between  the  line  of  the  horizontal  limb  of 
the  fissure  of  Sylvius  and  the  line  of  the  superior  temporo-sphenoid  fissure.  The 
middle  temporo-sphenoid  convolution  corresponds  to  the  interval  between  the  lines 
of  the  superior  and  middle  temporo-sphenoid  fissures. 

Individual  Variations  and  How  to  Determine  Them. — It  is  to  be  borne  in 
mind  that  the  brain  of  one  individual  ditt'ers  from  that  of  another,  and,  therefore, 
there  is  no  method  which  will  in  all  instances  represent  the  jiosition  of  the  fissures 
and  convolutions  with  absolute  correctness.  After  the  brain  cortex  is  exposed  in 
an  operation,  the  Faradic  current  can  be  applied  to  decide  what  portion  of  the 
motor  area  of  the  cortex  has  been  exposed.  It  can  be  readih'  api^reciated  that 
through  so  small  an  opening  as  that  made  l)y  the  trephine  it  is  scarcely  possible 
to  recognize  special  fissures  and  convolutions,  especially  when  we  recollect  how 
difficult  it  is  at  times  to  locate  them  in  the  dissection  of  the  brain. 

Indications  for  Trephining. — Excluding  trejihining  for  fracture  of  the  skull, 
the  cranial  cavity  is  opened  for  one  of  several  purposes — namely,  to  expose  the 
superior  and  inferior  maxillary  nerves  when  it  is  puqiosed  to  excise  one  or  both 
for  trifacial  neuralgia  ;  for  the  removal  of  the  Gasserian  ganglion,  as  described  ; 
to  remove  a  blood  clot ;  to  control  hemorrhage  from  one  or  both  branches  of  the 
middle  meningeal  artery  ;  to  open  the  lateral  sinus  in  septic  thrombosis  consequent 
upon  middle  ear  disease  ;  to  remove  part  of  the  brain  cortex,  as  in  Jacksonian 
epilepsy  ;  to  remove  a  brain  tumor  or  a  foreign  body ;  to  evacuate  an  abscess ;  to 
relieve  intra-cranial  pressure  ;  to  tap  tlie  lateral  ventricles  ;  for  the  relief  of  other- 
wi.se  uncontrollable  headache  when  the  point  of  greatest  pain  can  be  located  ;  and 
for  traumatic  epilepsy. 

To  Expose  the  Lateral  Sinus. — In  septic  thrombosis  of  the  lateral  sinus  con- 
sequent upon  middle  ear  disea.se  that  portion  of  the  sinus  in  relation  witli  the 
mastoid  process,  the  sigmoid  jiortion,  is  ex])osed.  To  reach  this  portion,  first  draw 
t\v(i  lines,  one  vertical  tlirougli  the  middle  of  the  mastoid  process,  and  a  second  on 
a  level  witli  tlic  roof  of  tlie  I'.xlrrual  auditory  meatus  and  at  a  right  angle  to  the 
first.  At  the  ])oint  of  junction  of  these  two  lines  apply  the  center  pin  of  a  one-inch 
trephine.  The  most  superficial  portion  of  this  sinv;s  is  not  so  deeply  situated  as 
the   ma.stoid  antrum,  being,  as  a   rule,  about  one-fourth  of  an  inch,  or  six  milli- 


cramo-('i:rei;ral  topogkaphy.  511 

nipters,  iVoni  llio  surface  nC  tin'  bone.  Befoi'c  removing  the  clot  f'nnii  tlie  sigmoid 
sinus  the  internal  jugular  \-cin  sliould  ln'  ligated,  to  control  hemorrhage  and 
prevent  dissemination  of  emboli.  As  a  thrombus  of  the  sigmoid  sinus  seldom 
occurs  except  as  a  complication  of  disease  of  the  masstoid  antrum,  the  latter  is 
usualh'  opened  first,  and  then  it  is  desirable  to  expose  the  sinus  on  its  anterior 
aspect  by  removing  the  bony  tissue  .between  tlie  antrum  and  the  sinus,  which 
often  contains  the  channels  through  which  the  sinus  has  become  infected. 

Localized  Affections. — In  oiierating  for  focal  epilepsy,  brain  tumor,  or  l)lood 
clot  the  trephine  is  applied  to  the  skull  directly  over  the  part  of  the  brain  believed 
to  be  the  site  of  involvement,  as  determined  by  localizing  symptoms.  The  lines 
which  indicate  the  courses  of  the  fissures  are  the  principal  guides. 

Foreign  Bodies. — In  the  removal — or  perhaps  it  would  be  better  to  say  the 
attempt  at  removal — of  a  foreign  body,  as  these  are  mo.st  commonly  Indlets  and  in 
the  majority  of  cases  located  with  difficulty,  the  cranial  cavity  is  attacked  at  the 
wound  of  entrance.  The  operation  of  trephining  in  this  class  of  cases  increases 
the  chance  of  finding  the  foreign  body  and  e.stablishes  drainage. 

Temporo-sphenoid  Abscess. — The  most  common  forms  of  intra-cranial 
abscess  are  temporo-sphenoid,  cerebellar,  and  extradural,  whicli  are  usually 
the  result  of  middle  ear  disea.se.  In  operating  for  temporo-sphenoid  abscess, 
which  is  usually  located  in  the  posterior  half  of  the  lobe,  first  draw  two  parallel 
lines  at  right  angles  to  Reid's  base  line,  the  anterior  passing  through  the  center 
of  the  external  auditory  meatus,  and  the  other  about  one  and  one-fourth  inches, 
or  three  centimeters,  behind  it.  Apply  the  center  pin  of  the  trephine  over  a 
point  one  and  one-fourth  inches,  or  three  centimeters,  above  Reid's  base  line  and 
between  the  two  vertical  lines  (Barker). 

Cerebellar  Abscess. — In  operating  for  cerebellar  abscess,  which  is  usually 
situateil  in  the  front  and  outer  part  of  the  hemisphere  of  the  cerebellum,  apply  the 
center  pin  of  the  trephine  at  a  point  one  and  one-half  inches,  or  four  centimeters, 
behind  the  center  of  the  external  auditory  meatus,  and  one  inch,  or  two  and  one- 
half  centimeters,  below  Reid's  base  line  (Barker). 

Extradural  Abscess. — Tlie  point  over  which  to  trephine  in  extradural  or 
subdural  abscess  must  depend,  in  a  great  degree,  upon  the  presence  of  localizing 
symptoms.  The  constitutional  evidences  of  pus  and  the  history  of  the  case, 
togetlier  with  circumscribed  edema  and  localizing  .symptoms,  such  as  spastic  con- 
traction or  paresis  of  certain  muscles,  would  constitute  the  most  reliable  guides. 
Septic  meningitis,  as  far  as  the  constitutional  symptoms  are  concerned,  frequently 
so  clo.«ely  simulates  cerebral  abscess  that  a  differential  diagnosis,  in  tlie  absence  of 
localizing  symptoms,  is  impossible. 

To  Tap  the  Lateral  Ventricles  apply  the  center  pin  of  the  tiephine  one  and 


512  SURGICAL   ANATOMY. 

one-quarter  inches,  or  three  centimeters,  behind  the  center  of  the  external  auditory 
meatus  and  the  same  distance  above  Reid's  base  hne.  The  ventricle  is  reached  by 
carrying  a  grooved  director  obliquely  forward  and  upward  toward  a  point  two  and 
one-half  to  three  inches,  or  six  to  seven  and  one-half  centimeters,  above  the  ojipo- 
site  external  auditory  meatus.  The  distance  to  which  the  grooved  director  must 
be  inserted  to  reach  the  ventricle  is  from  two  to  two  and  one-quarter  inches,  or  five 
to  five  and  one-half  centimetei's  (Keen). 

Headache  and  Traumatic  Epilepsy. — In  otherwise  uncontrollable  headache, 
when  the  point  of  greatest  pain  can  be  located,  the  trephine  is  applied  at  that 
point.  In  traumatic  epilepsy  the  trephine  is  ajiplied  to  the  site  of  the  original 
injury. 

Craniectomy,  or  removal  of  a  .section  of  the  calvaria  to  allow  expansion  of 
the  brain  in  cases  of  idiocy,  is,  in  the  author's  opinion,  inadvisable,  and  might  be 
compared  to  removal  of  a  section  of  a  nutshell  to  allow  increased  growth  of  a 
nut,  the  kernel  of  which  is  dead. 


THE  INTERIOR  OF  THE  CEREBRUM. 

Material. — In  order  to  study  the  brain  to  the  best  advantage  the  dis.sector,  as 
previously  remarked,  should  have  at  least  two  preserved  brains  at  his  disposal. 
One  brain  may  be  u.sed  for  the  study  of  the  fissures,  convolutions,  and  interior  of 
the  brain  ;  and  the  other  f(.>r  making  sections  of  the  l)rain. 

Dissection. — Having  completed  the  study  of  the  fissures  and  the  convolu- 
tions, next  examine  the  interior  of  the  cerebrum.  Place  the  brain  on  its  base,  and 
sei^arate  the  hemispheres  of  the  cerebrum,  to  widen  the  longitudinal  fissure,  thus 
exposing  the  bottom  of  the  fissure.  This  is  formed  in  great  jJart  by  a  mass  of 
Avhite  matter, — the  corpus  callosum,  or  the  great  transverse  commissure  of  the 
cerebrum, — while  in  front  of  and  behind  the  corpus  callosum  the  fissure  extends 
without  interruption  to  the  base  of  the  brain.  Make  a  horizontal  section  of  one  or 
both  hemispheres  on  a  level  with  the  floor  of  the  longitudinal  fissure.  AVhen  both 
hemispheres  are  sliced  away  to  the  level  of  the  fioor  of  the  longitudinal  fissure,  the 
upper  surface  of  the  corpus  callosum  is  well  exposed.  The  corpus  callosum  can 
now  be  studied  from  two  points  of  view  :  from  al)Ove  in  tbe  present  dissection,  and 
from  tlie  siile  l)y  looking  at  its  sagittal  section,  seen  in  the  preparation  previously 
made  liy  .severing  the  two  halves  of  the  lirain  in  the  line  of  the  longitudinal 
fissure. 

The  Corpus  Callosum,  tlie  great  transverse  commissure  of  the  cerebrum,  is  a 
tran.sverse  band  of  white  matter  which  s|)ans  the  longitudinal  fissure  and  connects 
the  hemispheres  of  the  cerebrum  for  ne;u-ly  half  their  length.     The  ful.c  cerebri 


PLATE  CXXV. 


Anterior  cerebral  a. 


White  matter 

Grey  matter 


Median  raphe' 


Strioe  longltudinales 


S—        II-  3;>, 


CORPUS  CALLOSUW  AND  HORIZONTAL  SECTION  OF  CEREBRUM, 
513 


PLATE  CXXVI, 


Body  of  corpus  callosum 
Velum  interpositum 
Fornix 
Paracentral  sulcus 
Foramen  of  Monro 
Gyrus  fornicatus 
Lateral  ventricle 


Callosal  fissura 
Calloso-marginal  fissure 
Marginal  convolution 


Paracentral   loLule 

Peduncle  of  pineal  l:)ody 

Fissure  of  Rolando 

Pineal  body 

Pia  mater  entering  third  ventricle 

Splenium  of  corpus  callosum 

Subparietal  sulcus 

Tela  choroidea  inferior 

Quadrate  lobe  or  precuneus 

Calcarine  fissure 

Parieto-occipital 
fissure 

Cuneus 


Genu  of  corpus  callosum 

Septum  lucidum  (cut) 
Fifth  ventricle 
Anterior  commissure' 

Optic  n'. 

Optic  commissure 

Lamina  cinerea 
Anterior  pillar  of  fornix 
Pituitary  body 
Third  Ventricle 
Optic  thalamus 
Tuber  cmereum 


Cerebellum 


Arbor  vitae 
Medulla  oblongata 
Fourth  ventricle 
Superior  medullary  velum 
Corpora  quadragemina 
Pons  Varolii 
Aqueduct  of  Sylvius 
Posterior  commissure 
Crus  cerebri 


Corpus  albicans     Middle  commissure 


INTERNAL  SURFACE  OF  CEREBRUM 


SECTION  OF  VENTRICLES  OF  BRAIN, 


510 


THE  INTERIOR   OF   THE  CEREBRUM.  617 

touches  the  posterior  portion  of  tiie  eorpu.s  caliosuni  ;  the  greater  part  of  the  body 
of  the  corjius  callosuin  and  its  anterior  extremity  are  separated  for  a  considerable 
distance  from  tiie  ialx  cerebri.  Tlie  corpus  callosum  is  sHghtly  convex  from  before 
backward  on  the  upper  surface,  is  between  three  and  four  inciies,  or  seven  to  ten 
centimeters,  in  length,  and  extends  nearer  to  the  anterior  tlian  to  tlie  posterior  end 
of  the  cerebrum.  It  is  wider  beliind,  wiiere  it  measures  about  one  inch,  or  two  and 
one-half  centimeters,  and  is  thicker  at  each  end,  especiallj'  at  the  posterior  extremity, 
than  in  the  middle.  It  forms  the  roof  of  the  lateral  ventricles,  which  are  cavities 
located  within  the  hemispheres  of  the  cerebrum.  On  its  dorsal  surface,  extending 
along  its  middle  line,  a  liut-ar  depression  exists,  the  raphe.  On  each  side  of  the 
rai)lie,  and  running  parallel  with  it,  are  two  slightly  elevated  longitudinal  bands, 
tlie  striae  longitudinales,  <ii-  nerves  of  Lancisi.  External  to  these  are  the  faintly 
marked  striae  longitudinales  laterales,  or  taeniae  tectae,  which,  with  the  brain 
intact,  underlie  the  convolutions  of  the  corpus  callosum,  or  gyri  fornicati.  The 
taeniae  tectfe  are  separated  Imudles  of  a  group  of  fil)ers  known  as  the  cingulum, 
which  forms  part  of  the  callnsal  and  liippocampal  gj'ri.  The  fibers  proper  of  the 
corpus  callosum  run  transversely,  as  its  name,  the  great  transverse  commissure, 
implies.  The  corjius  callosum  consists  of  a  main  portion  or  body,  seen  best  on 
longitudinal  section,  and  of  two  extremities,  tlie  anterior  and  the  posterior. 

The  anterior  extremity,  or  genu,  is  formed  by  the  bending  downward  and 
then  backward  of  the  corpus  callosum  ;  from  this  bend  it  is  continued  to  the  base 
of  the  brain  as  the  beak,  or  rostrum,  wliicli  is  the  reflected  portion  of  the  genu,  and 
is  thin  and  narrow.  Within  the  concavity  of  the  genu  is  situated  the  sei^tum  luci- 
dum,  which  contains  between  its  layers  the  fifth  ventricle.  The  rostrum  of  the 
corpus  callosum  has  previously  been  described  with  the  base  of  the  brain  ;  it  is 
connected  to  the  tuber  cinereum  by  the  lamina  cinerea.  It  gives  off  two  bands  of 
white  substance,  which  are  continuations  of  the  nerves  of  Lancisi  and  form  the 
peduncles  of  the  corpus  callosum.  These  then  diverge  from  each  other  and  run 
backward  and  outward  across  the  anterior  perforated  space  to  the  tips  of  the  tem- 
poral lobes,  meeting  the  inner  roots  of  the  olfiictorj^  tracts.  Tlie  fibers  from  the 
genu  of  the  corpus  callosum  pass  outward  and  forward  and  then  inward,  into  the 
prefrontal  region,  forming  the  forceps  minor. 

The  posterior  extremity  of  the  corpus  callosum,  or  splenium,  is  formed  by 
a  bending  of  the  corpus  callosum  downward  and  forward  upon  itself,  thus  making 
a  free,  thickened,  rounded  border.  This  border  Ibrms  the  upper  boundary  of  the 
central  part  of  the  transverse  fissure,  and  beneath  it  pa.sses  the  process  of  the  pia 
mater  known  as  the  velum  interpositum.  The  splenium  is  connected  anteriorly 
with  the  fornix.  The  fibers  of  the  splenium  which  curve  outward  and  backward 
over  the  posterior  horn  of  the  lateral  ventricle  constitute  {he  forceps  major ;  some 


518  SURGICAL  ANATOMY. 

of  these  fibers  form  a  long,  rounded  elevation,  the  bulb  of  the  posterior  cornu  of 
the  lateral  ventricle. 

The  under  surface  of  the  bodv  of  the  corpus  callosum  is  connected  along  the 
middle  line  with  the  fornix  and  the  septum  lucidum,  while  laterally  it  forms  the 
roof  of  the  lateral  ventricles. 

Dissection. — Make  two  sagittal  incisions  from  before  backward,  tlirough  tlie 
corpus  callosum,  from  three-eighths  to  one-half  an  inch,  or  one  centimeter,  to  each 
side  of  the  median  line ;  this  will  open  the  lateral  ventricles — cavities  which 
occupy  the  interior  of  the  hemispheres  of  the  cerebrum.  To  expose  the  interior 
of  one  or  both  lateral  ventricles  so  as  fully  to  disclose  the  contained  structures,  cut 
away  with  a  pair  of  scis.sors  as  much  of  the  corpus  callosum  on  each  side  of  the 
incision  as  may  be  necessary.  This  dissection  will  not  open  the  middle  or  descend- 
ing cornu  ;  to  accomplish  tliis  a  section  of  the  lateral  portion  of  the  hemisphere 
(temporo-sphenoid  lobe)  must  be  removed.  This  can  be  done  either  from  without 
inward  or  from  within  outward  by  following  the  course  of  the  cornu  with  the 
scalpel. 

The  Lateral  Ventricles  (trihorned  ventricles,  ventriculi  tricornes)  are  two 
irregularly  shaped  cavities,  one  of  which  is  situated  in  each  hemisphere  of  the  cere- 
brum. They  communicate  with  the  third  ventricle  by  way  of  the  foramina  of 
Monro,  and  tfirougli  tlie  third  ventricle  with  the  fourth  ventricle,  by  way  of  the 
aqueduct  of  Sylvius,  or  iter  e  tertio  ad  quartum  ventriculum.  They  are  lined  by  a 
membrane,  the  ependyma,  whose  function  is  to  secrete  part  of  the  cerebro-spinal 
fluid.  Each  of  the  ventricles,  which  are  separated  in  front  by  a  vertical  partition, 
the  sejitum  lucidum,  consists  of  four  parts :  a  body,  or  central  portion,  and  three 
horns,  or  cornua.  The  cornua  are  designated  anterior,  middle  or  descending,  and 
posterior,  and  extend,  respectively,  into  the  frontal,  the  temporo-sphenoid,  and  the 
occipital  lobe  of  the  cerebrum. 

The  body  of  the  lateral  ventricle  is  triangular  in  shape  in  a  coronal  section, 
its  antero-posterior  diameter  being  the  longest,  and  its  vertical  diameter  the 
shortest.  It  extends  from  the  foramen  of  Monro  to  the  splenium  of  the  corpus  cal- 
losum. It  is  bounded  a})Qvc  by  the  corpus  callosum  ;  internalhi,  by  the  posterior 
naiTow  portion  of  the  septum  lucidum,  and  the  attacliment  of  tlie  corjius  callosum 
to  the  fornix  ;  ami  rxfentalh/,  by  tiie  merging  angle  formed  b}^  the  corj)US  cal- 
losum and  the  white  sul)stance  of  the  hemisphere.  Its  floor  is  formed  bv  the  fol- 
lowing [)arts,  named  in  their  order  from  without  inward  :  the  intra-ventricular  por- 
tion of  the  corpus  striatum,  or  caudate  nucleus,  the  trenia  semicircularis  and  a 
small  vein  of  tlio  corpus  striatum  contained  in  iiu  olilicpie  groove,  the  optic  thala- 
mus, the  choroid  ])lcxus,  half  of  the  body  of  tiic  fornix,  with  its  lateral  edge  or 
corpus  fiinlirialiiiii. 


PLATE  CXXVIl 


Corpus  fimbriatum 
Choroid  plexus, 
Optic  Thalamus 
Tenia  semicircularis 


Corpus  striatum 

Corpus  callossum 

Location  of  foramen  of  Monro 


Hippocampus  major 


Eminentia  collateralis 
Hippocampus  minor 
Bulb  of  posterior  cornu 


BODIES,  ANTERIOR  CORNUA,  AND   POSTERIOR  CORNUA  OF  LATERAL  VENTRICLES. 

519 


THE  INTERIOR    OF  THE   CEREBRUM.  521 

The  anterior  cornu  of  the  lateral  ventricle  is  tri;m<;ul:ir  in  sliapc  on  coionjil 
section  of  tlie  brain.  It  extends  forward,  downward,  and  outward  into  tiu;  frontal 
iol»e.  It  curves  around  the  anterior  end  of  tlie  corpus  striatum,  and  diverges  from 
the  anterior  cornu  of  the  lateral  ventricle  of  the  otlier  side  as  it  passes  forward.  It 
is  bounded  above  bj-  the  fibers  of  the  corpus  callosum  {forceps  minor),  which  curve 
outward  and  forward;  intcnKi/li/,  \>y  the  scjituni  luciiluni,  wiiicli  separates  it  from 
the  corresponding  cornu  of  the  opposite  ventricle;  m  front,  by  the  genu  of  the 
corpus  callosum  ;  and  externally,  liy  the  caudate  nucleus.  Its  _^oor  is  formed  in 
great  part  by  the  caudate  nucleus,  which  projects  into  it,  and  to  a  slight  extent  In' 
the  I'ostrum  of  the  corpus  callosum. 

The  posterior  cornu  of  the  lateral  ventricle,  tin-  smallest  of  the  three  cornua, 
commences  in  the  body  of  the  ventricle  ojiposite  the  splenium  of  the  corpus  callo 
sum,  and  at  the  same  point  as  the  middle  cornu.  It  extends  horizontally  back- 
ward, outward,  and  then  inward  into  the  occipital  lobe.  Its  roof  is  formed  by 
tlio.se  fibers  of  the  sjjlenium  of  the  corpus  callosum  (forceps  major)  which  pass  back- 
ward and  outward  and  become  continuous  with  the  white  matter  of  the  occipital 
lobe.  On  its  inner  wall  is  seen  the  hi[)pocampus  minor,  or  calcar  avis,  produced 
by  the  calcarine  fissure  ;  above  this  is  a  smaller  prominence,  the  bull)  of  the  cornu, 
produced  by  the  bulging  of  the  fibers  of  the  forceps  major  into  the  cavity,  above 
and  internal  to  the  hippocampus  minor.  On  the  floor  is  seen  a  slight  elevation, 
produced  by  the  fasciculus  longitudinalis  inferior,  which  passes  from  the  occipital 
to  the  temporal  lobe.  At  the  point  where  the  middle  and  posterior  cornua 
meet  a  triangular,  smooth  surface  is  seen,  called  by  Schwalbe  the  trigonum 
ventriculi. 

The  middle  or  descending  cornu  of  the  lateral  ventricle,  tlie  longest  of  the 
three  cornua,  may  be  considered  tlie  continuation  of  the  cavity  of  the  ventricle 
into  the  temporal  lobe  ;  it  commences  ojiposite  the  splenium  of  the  corpus  callosum, 
in  the  body  of  the  ventricle,  at  the  same  point  at  which  the  posterior  cornu  begins. 
It  extends  backward  and  outward  around  the  posterior  extremity  of  the  optic  thala- 
mus, and  then  runs  downward,  forward,  and  inward  to  reach  the  base  of  the  brain, 
terminating  about  an  inch,  or  2.5  centimeters,  from  the  tip  of  the  temjioro-sphenoid 
lobe.  Its  roof  is  formed  by  those  fibers  of  the  body  of  the  corjius  callosum  (tape- 
tum)  which  pass  outward  and  become  continuous  with  the  white  matter  of  the 
temporo-sphenoid  lobe,  and  by  the  tail  of  the  caudate  nucleus,  the  ta'uia  semi- 
circularis,  and  the  amygdaloid  tubercle.  T\iv  floor  is  foiincil  in  great  part  by  the 
eminentia  collateralis.  Upon  the  inner  ivall  are  seen  the  following  structures, 
named  from  without  inward  :  the  hippocampus  major,  and  pes  hippocampi,  the 
corpus  fimliriatum,  the  choroid  plexus,  and  the  fascia  dentata  or  dentate 
convolution. 


522  SURGICAL  ANATOMY. 

Dissection. — Next  make  a  transverse  section  of  the  remaining  portion  of  the 
body  of  tlie  corpus  callosum  at  about  its  middle,  and  dissect  one  half  forward 
and  the  other  half  backward.  If  carefully  executed,  this  dissection  exposes  the 
fornix  and  the  septum  lucidum. 

The  Fornix,  the  longitudinal  commissure  of  the  cerebrum,  is  a  triangular 
mass  of  white  matter  situated  beneath  the  corpus  callosum,  and  is  continuous 
posteriorly  with  the  splenium  of  the  corpus  callosum.  It  overlies  the  velum 
interpositum,  which  separates  it  from  the  third  ventricle  and  the  optic  thal- 
amus. It  consists  of  a  main  portion,  or  body,  and  an  anterior  and  a  i^osterior 
crura. 

The  body  of  the  fornix  is  triangular  in  shape,  the  apex  of  the  triangle 
being  directed  anteriorly.  The  fornix  is  adherent  behind  to  the  splenium  of  the 
corpus  callosum,  and  is  attached  above  and  in  front  to  the  septum  lucidum,  and 
above  and  behind  to  the  corpus  callosum  ;  below,  it  rests  upon  the  velum  interpos- 
itum, and  lies  above  the  third  ventricle.  The  sides  of  the  body  of  the  fornix  pro- 
ject into  the  lateral  ventricles,  overlapping  the  inner  portion  of  the  optic  thalami 
and  choroid  plexuses.  The  fibers  of  the  under  surface  of  the  fornix  behind  are  so 
arranged  as  to  give  rise  to  the  designation  the  lyre,  which  has  been  bestowed  upon 
them. 

The  anterior  crura,  or  pillars  of  the  fornix,  are  two  cylindric  bundles  of 
nerve-fibers  which  are  given  off  from  the  anterior  extremity  or  apex  of  the  body  of 
the  fornix,  whence  they  diverge' and  descend  in  front  of  the  optic  thalami  and  the 
foramina  of  Monro  and  then  through  the  gray  matter  in  the  sides  of  the  third  ven- 
tricle, to  the  base  of  the  brain,  where  thej^  form  the  white  matter  of  the  corpora 
albicantia,  or  mammillary  eminences.  Fibers  pass  from  the  corpora  albicantia  to 
the  optic  thalami ;  these  fibers  constitute  the  bundles  of  Vicq  d'Azyr,  and  are 
probably  not  directly  continuous  with  the  fibers  of  the  fornix.  In  their  descent 
the  anterior  pillars  are  joined  by  the  tsenise  semicirculares  and  hy  fibers  from  the 
septum  lucidum  and  peduncles  of  the  pineal  gland.  Between  the  anterior  crura 
and  the  anterior  extremities  of  the  optic  thalami  are  the  oval  openings  of  com- 
numication  between  the  lateral  ventricles  and  the  third  ventricle,  the  foramina 
of  Monro. 

Tlie  posterior  crura,  or  pillars  of  the  fornix,  arise  posteriorly  from  each  side 
of  the  body  of  the  fiiniix,  whence  they  diverge  and  descend  into  tlic  middle  cornua 
of  tlie  lateral  ventricles.  Here  each  cms  lies  within  the  concavity  of  the  curve 
described  by  the  hippocampus  major  as  fiir  as  tlie  pes  hippocampi.  The  lateral 
liordcrs  of  the  ]iost(>rior  crura  of  the  fornix  are  known  as  the  corpora  fimbriata, 
(ir  taeniae  hippocampi. 

Tlie  septum  lucidum  is  a  triangular  vertical  partition  situated  between  the 


PLATE  CXXVIII. 


Tenia  semicircularis 
Optic  thalamus 

Pia  mater  entering  at 
hippocampal  fissure 
^^choroid  plexus  removed) 

Pes  hippocamp 


Genu  of  corpus  callosum 
Fifth  ventricle 
Septum  lucidum 
Corpus  striatum 


Hippocampus  major 
Eminentia  collateralis' 


Hippocampus  minor 
Bulb  of  posterior  cornu 

of  lateral  ventricle 


Choroid  plexus 

Fornix 
Splenium  of  corpus  callosum 

Posterior  pillar  of  fornix 


FORNIX  AND  LATERAL  VENTRICLES,  AND   DESCENDI^ 

523 


U  OF  LEFT  LATERAL  VENTRICLE. 


THE   IXTKIUOR    OF   THE      'RKBKUM.  525 

anterior  portion  of  the  bodies  of  tlie  two  lateral  ventricK's  and  between  the  anterior 
eornua  of  those  ventricles.  The  base  of  the  triangle  is  directed  downward  and 
forward,  and  the  apex  backward,  into  the  narrow  interval  between  the  anterior  part 
of  the  body  of  the  fornix  below,  and  the  corpus  callosum  above.  The  septum 
lufiilum  is  attached  above  to  the  under  surface  of  the  body  of  the  corpus  callosum  ; 
in  front,  to  the  concavity  of  the  genu  ol'  tlie  corpus  callosum  ;  and  below,  to  the 
rostrum  of  the  corpus  callosum  and  to  the  body  and  anterior  crura  of  the  fornix. 
It  is  composed  of  two  lamina?,  between  which  is  the  cleft-liko  interval  known  a 
the  fifth  ventricle. 

The  fifth  or  Sylvian  ventricle  is  not  provided  with  an  outlet,  but  is  a  com- 
pletely inclosed  space.  Each  of  the  lamin;e  of  the  septum  lucidum,  which  bound 
this  ventricle  laterally,  consists  of  an  inner  gray  layer,  a  middle  white  layer,  and 
an  outer  layer  of  ependyma  which  is  part  of  the  ependyma  that  lines  the  lateral 
ventricles.  The  fifth  ventricle  differs  from  tlie  other  ventricles  in  its  mode  of 
development ;  it  is  a  portion  of  the  great  longitudinal  fissure  which  has  become 
inclosed  by  the  formation  of  the  corpus  callosum  and  fornix. 

Dissection. — With  a  pair  of  scissors  slice  away  a  horizontal  section  from  the 
superior  portion  of  the  septum  lucidum,  when,  with  a  little  care,  the  laminte  can 
be  pushed  apart  and  the  fifth  ventricle  opened.  Should  the  ventricle  contain  more 
than  the  usual  quantity  of  fluid,  it  can  lie  more  readily  seen  tlian  if  it  were  in  a 
normal  state. 

Before  reflecting  the  fornix  examine  the  structures  seen  within  the  lateral 
ventricle,  commencing  with  the  corpora  striata,  wliicli  project  into  the  anterior 
eornua. 

Corpus  Striatum. — The  corpora  striata  (anterior  cerebral  ganglia)  are  the 
anterior  [lair  of  basal  ganglia.  The  })ortion  seen  within  the  anterior  cornu  of  the 
lateral  ventricle  is  the  intra-ventricular  portion,  or  caudate  nucleus.  It  is  so 
called  in  contradistinction  to  the  larger  extra-ventricular  portion,  or  lenticular 
nucleus,  which  occupies  the  white  substance  of  tlie  hemisphere  of  the  cerebrum. 
To  expose  both  the  lenticular  nucleus  and  the  caudate  nucleus  in  one  dissection  it 
is  necessary  to  make  horizontal  sections  of  the  hemisphere  ;  these  sections  will  be 
described  further  on. 

The  Caudate  Nucleus  is  a  pear-shaped  mass  of  gray  matter  having  its  broad 
extremity,  or  head,  directed  forward  into  the  forepart  of  the  body  and  the  anterior 
cornu  of  the  lateral  ventricle,  and  its  narrow  extremity,  or  tail,  directed  outward 
and  backward.  It  lies  to  the  outer  side  of  the  optic  thalamus,  and  is  prolonged  into 
the  roof  of  the  middle  horn  of  the  lateral  ventricle  as  far  as  its  anterior  ex- 
tremity, where  it  terminates  in  the  amygdaloid  tubercle.  Crossing  the  surface  of 
the   caudate  nucleus  are  numerous   small   veins   emptying  into  the  vein  of  the 


526  SURGICAL  ANATOMY. 

corpus  striatum,  which  Ues  in  the  groove  between  the  caudate  nucleus  and  tlie 
optic  thalamus. 

The  Taenia  Semicircularis,  or  Stria  Terminalis,  is  a  very  narrow  longitudinal 
band  of  white  fibers,  which  lies  in  the  groove  between  the  caudate  nucleus  and  the 
optic  thalamus,  and  conceals  from  view  the  vein  of  the  corpus  striatum.  It  extends 
from  the  anterior  crus  of  the  fornix,  with  which  it  is  continuous  in  front,  back- 
ward through  the  floor  of  the  body  of  the  ventricle,  and  into  and  along  the  roof 
of  the  middle  cornu  as  far  as  the  amygdaloid  tubercle,  where  it  ends.  Where 
the  surface  of  the  anterior  portion  of  the  taenia  semicircularis  is  more  transparent 
and  less  dense  than  elsewhere  was  called  ])y  Tarinus  the  "Imrny  l)and." 

The  Optic  Thalami  (posterior  cerebral  ganglia),  the  posterior  pair  of  basal 
ganglia,  can  not  be  seen  to  advantage  at  this  .stage  of  the  dissection,  without  dis- 
arranging the  parts  overlying  them  and  until  the  fornix  and  the  velum  interposi- 
tum  have  been  removed  ;  their  description,  therefore,  will  be  deferred.  It  is  suffi- 
cient to  say  here  that  the  optic  thalamus  is  an  oblong  mass  of  white  and  gray 
matter  Ij'ing  to  the  inner  side  of  the  caudate  nucleus  and  the  taenia  semicircularis, 
part  of  the  upper  surface  of  which  is  hidden  by  the  choroid  plexus,  the  corpus 
fimbriatum,  and  the  lateral  portion  of  the  body  of  the  fornix. 

The  Choroid  Plexus  is  a  red,  convoluted,  vascular  fringe,  formed  in  the  free 
margin  of  the  velum  interpositum,  extending  from  the  foramen  of  Monro  back- 
ward over  the  optic  thalamus  into  the  descending  cornu  of  the  lateral  ventricle, 
where  it  lies  on  the  hippocampus  major  and  extends  to  the  end  of  tliis  cornu  of 
the  ventricle.  It  is  covered  throughout  by  the  ventricular  epithelium,  or  epen- 
dyma,  which  passes  from  the  corpus  fimbriatum  to  the  taenia  semicircularis  and 
optic  thalamus ;  the  ependyma  thus  separates  the  plexus  from  the  cavity  of  the 
ventricle.  Behind  and  between  the  foramina  of  Monro  the  choroid  plexus  of  one 
lateral  ventricle  becomes  continuous  with  that  of  the  other,  and  from  the  point  of 
junction  the  choroid  plexuses  of  the  ventricle  extend  backward. 

The  Corpus  Fimbriatum,  Taenia  Hippocampi,  or  Fimbria,  a  narrow  band  of 
white  matter,  is  the  edge  of  the  posterior  crus  of  the  fornix,  which  rests  upon  the 
posterior  end  of  the  optic  thalamus,  the  choroid  plexus  intervening,  and  is  con- 
tinued into  the  descending  cornu  of  the  lateral  ventricle.  Here  it  rests  between 
the  concave  margin  of  tiie  hij)pocami)Us  major  and  the  pia  mater,  whicli  passes 
through  the  hippocampal  fissure.  It  extends  as  far  as  the  uncus  of  the  hippo- 
campal  gyrus. 

TI:u  Hippocampus  Major,  or  Cornu  Ammonis,  is  the  prominent  convex,  white 
cniincucc  wliich  forms  p;irt  <ir  the  floor  and  inner  wall  of  the  descending  cornu  of 
the  liilrf.'il  ventricle,  and  extends  througiiout.  tlie  entire  length  of  tiiis  cornu.  It 
is  jiriiihiccd  liy  extension  of  the  liippocanipal   llssurc  into  the  descending  cornu  of 


PLATE  CXXIX. 


Anterior  cornu  of 

lateral  ventricle 


Body  oF  lateral  ventricle 
Middle  cornu  of 
lateral  ventricle 


Foramina  of  Monro 


I  bird  ventricle 


DIAGRAM  OF  THE  VENTRICLES-SUPERIOii  VIEW. 
528 


PLATE  CXXX. 


Peduncle  of  pineal  body  Notch  for  posterior  commissure 


Perforation  for  middle  commissure. 
Foramen  of  Monro 


Anterior  cornua  of 
lateral  ventricles 


Bodies  of  lateral  ventricles 

Hippocampus  major 

Bulb  of  posterior  cornu 
Hippocampus  minor 


Caudate  nucleus 

Notch  for  anterior  commissure 

Anterior  pillar  of  fornix  I  III  Fourth  ventricle 

Third  ventricle  1    |       )  Aqueduct  of  Sylvius 

Middle  cornua  of  lateral  ventricles'    |      Corpus  fimbriatum 
Pes  hippocampi 


Posterior  cornua  of 
lateral  ventricles 


S— 


1 1  -.'A 


DIAGRAM  OF  THE  VENTRICLES-LATERAL  VIEW, 
529 


THE  INTERIOR    OF  THE   CEREBRUM.  531 

the  lateral  ventricle.  Along  its  antero-superior  or  concave  margin  is  the  corpus 
finibriatum.  Its  anterior  extremity,  the  pes  hipjiocampi,  is  enlarged,  and  presents 
two  or  more  grooves,  so  that  it  sonicwluit  resembles  the  j)a\v  of  an  aninuil. 

DiSSECTiox. — t'avefully  sei)arato  the  \\\nvY  Ixn'ilcr  of  tlie  corjius  timl)riatuni 
from  tlu>  choroid  plexus  of  the  descending  cornu  of  the  lateral  ventricle,  thus 
breaking  through  the  epithelial  lining  of  the  ventricle  ;  displace  the  choroid  plexus 
inward,  and  slightly  depress  the  corpus  fimbriatum  and  hippocampus  major.  Tliis 
{irocedure  exposes  the  fascia  dentata,  and  separates  the  margins  of  the  hippocampal 
fissure. 

The  Fascia  Dentata,  or  Dentate  Convolution,  a  serrated  band  of  gray  matter, 
is  the  margin  of  the  hippocampal  convolution  in  relation  with  the  hippocampal 
fissure.  The  serrations  or  indentations  of  the  fascia  dentata  are  produced  by  the 
vessels  of  the  pia  mater,  which  projects  through  the  hippocampal  fissure  into  the 
descending  cornu  of  the  lateral  ventricle.  The  fascia  dentata  extends  from  near 
the  splenimu  of  the  corpus  callosum  to  the  anterior  extremity  of  the  descending 
cornu  of  the  lateral  ventricle.  As  the  epithelial  lining  of  the  ventricle  must  be 
divided  in  order  to  expose  the  fascia  dentata,  that  convolution  is  external  to  the 
wall  of  the  ventricular  cavity. 

The  Hippocampus  Minor,  Calcar  Avis,  or  Ergot,  is  a  small,  convex,  white 
eminence  which  occupies  tlie  floor  and  inner  wall  of  tlie  posterior  cornu  of  the 
lateral  ventricle.  It  is  produced  by  the  calcarine  fissure,  and  is  at  times  but  faintly 
marked. 

The  Eminentia  Collateralis,  or  Pes  Accessorius,  may  be  recognized  at  its 
commencement  as  a  smooth  white  eminence  fitting  into  the  angle  of  divergence  of 
the  hippocampus  major  and  hippocampus  minor,  at  the  junction  of  the  middle 
and  posterior  cornua  of  the  lateral  ventricle.  It  extends  forward  as  the  floor  of 
the  middle  cornu  of  the  lateral  ventricle  almost  to  the  extremitj^  of  this  cornu. 
It  is  produced  by  the  collateral  fissure. 

Dissection. — Next  divide  the  fornix  transversely  at  about  its  middle,  and 
reflect  the  one  half  forward  and  the  other  backward,  thus  exposing  the  greater 
part  of  that  process  of  pia  mater — the  velum  interpositum — which  lies  above  the 
epithelial  roof  of  the  tliird  ventricle.  To  expose  thoroughly  the  velum  inter- 
po.situm,  especially  that  part  of  it  which  occupies  the  central  portion  of  the  trans- 
verse fissure,  make  a  longitudinal  incision  through  the  jwsterior  part  of  the  fornix 
and  corpus  callosum  ;  then  reflect  (liese  fla])s  laterally. 

The  Velum  Interpositum,  or  Tela  Choroidea  Superior,  is  that  process  of  the 
pia  mater  which  reaches  the  interior  of  the  brain  by  way  of  the  horizontal  portion 
of  the  transverse  fissure,  passing  1)etween  the  splenium  of  the  corpus  callo.sum  and 
the  corpora  quadrigemina.     It  is  a  double  layer  of  pia  mater,  and  is  triangular  in 


532  SURGICAL  ANATOMY. 

shape,  like  the  fornix  ;  it  lies  beneath  tlie  fornix  and  the  corpus  callosvuii.  It 
covers  the  quadrigeminal  bodies,  the  pineal  body,  the  third  ventricle,  and  part 
of  the  optic  thalami.  Its  borders  contain  the  choroid  plexuses  of  the  lateral  ven- 
tricles, while  in  its  under  surface  are  situated  the  two  choroid  plexuses  of  the  third 
ventricle.  The  latter  plexuses  are  continuous  with  the  choroid  plexuses  of  the 
lateral  ventricles  just  behind  the  foramina  of  Monro.  Running  one  on  each  side 
of  the  median  line  of  the  velum  interpo.situm,  between  its  two  layers,  are  the  two 
veins  of  Galen,  formed  by  the  union  of  the  veins  of  the  corpora  striata  and  the 
choroid  veins,  in  addition  to  small  twigs  from  surrounding  structures.  They  unite 
posteriorly  to  form  a  single  trunk,  which  joins  the  inferior  longitudinal  sinus  to 
form  the  straight  sinus  at  the  junction  of  the  inferior  margin  of  the  falx  cerebri 
with  the  anterior  margin  of  the  tentorium  cerebelli. 

Dissection. — Raise  the  velum  interpositum  and  the  choroid  plexuses  and 
turn  them  backward.  Especial  care  is  necessary  in  raising  the  posterior  part  of 
the  velum  interpositum  so  as  not  to  rai.se  the  pineal  gland  with  it,  as  the  gland  is 
closely  invested  by  the  lower  layer  of  jjia  mater  entering  the  velum.  This  dissec- 
tion exposes  the  third  ventricle,  the  three  commissures  of  that  ventricle,  the  anterior 
crura  of  the  fornix,  the  optic  thalami,  the  pineal  body  and  its  peduncles,  and  the 
quadrigeminal  body.  In  making  the  dissection  it  frequently  happens  that  the 
middle  commissure  of  the  third  ventricle  is  broken,  and  the  dissector,  if  not 
familiar  with  this  fact,  might  conclude  that  it  was  absent  in  the  brain  under  exam- 
ination. 

Fissure  of  Bichat. — Before  describing  the  parts  exposed  by  the  removal  of 
the  velum  interpositum,  the  great  transver.se  fissure  of  the  brain,  or  fissure  of 
Bichat,  which  is  now  opened  up  throughout,  should  be  carefully  observed.  To  do 
this  to  the  best  advantage  it  is  necessary  to  remove  the  velum  interpositum  and 
the  choroid  plexuses  of  the  lateral  and  third  ventricles  with  the  adherent  epi- 
thelium. The  central  horizontal  or  transver.se  portion  of  this  fissure,  through 
which  the  velum  interpositum  passes,  is  the  continuation  of  the  interspace  between 
the  cerebrum  and  the  cerebellum  seen  in  the  undissected  brain  with  the  pia  mater 
removed.  This  central  portion  is  contimious  with  the  lateral  portions,  or  hippo- 
campal  fissures,  which  are  seen  in  the  dissection  of  the  middle  cornua  of  the 
lateral  ventricles,  thus  making  the  fissure,  as  a  whole,  horseshoe  shaped. 

The  Third  Ventricle  is  a  narrow,  oblong  cavity  situated  in  the  middle  line  of 
the  cerebrum,  lietwecn  the  optic  thalami  and  the  peduncles  of  the  pineal  liody,  and 
reaching  to  the  base  of  tlio  brain.  It  is  wider  and  shallower  ln-liiiul  tlian  in  front. 
It  is  Itoundcd  alioir  by  tiic  velum  interpositum,  iiltlidu^li  its  immediate  roof  is 
formed  by  a  thin  epithelial  layer  which  is  contimious  with  llic  lining  epithelium 
or  ependyma  of  the  ventricle;  on  the  sides,  by  the  optic  tiialami  and  the  peduncles 


PLATE  CXXXI, 


Choroid  plexus 


Anterior  pillars  of  fornix(cut) 
Veins  of  Galen 


Descending  cornu  of  left  lateral  ventricle 


Velum  interpositum 
Body  of  fornixfreflected) 
Lyra 


VELUM   INTERPOSITUM  AND  CHOROID  PLEXUS. 


PLATE  CXXXII. 


Portion  of  corpus  callosum 
Anterior  commissure. 
Middle  commissure. 
Peduncle  of  pineal  body 

Posterior  commissure,     \     \  \ ^S^^  I 

Pineal  body, 
Choi-oid  plexus 


,Septum  lucidum 

rAnterior  pillar  of  fornix 
Head  of  caudate  nucleus 
Third  ventricle 
,Optic  tinalamus 
Tenia    scmicircularis 

Corpora  quadrigemina 


Superior  cerbellar  pedu 

Superior  medullary  velu 

Eminentia  teres 
Floor  of  fourtli  ventricle 
Trigonum  hypogloss 
Ala  cinerea' 
Tuberculum  acusticum      _, 
Restiform  body 


Hippocampus  major 
Posterior  pillar  of  fornix 
Cerebellum 
Hippocampal  fissure 
Fascia  dentata 
Lateral  column  of  medulla  oblongata 
Funiculus  cuneatus  of  medulla 
Funiculus  gracilis  of  medulla 


VENTRICLES  AND   NUCLEI  OF  THE  BRAIN. 


THE   IMT.Uloi;    OF   TIIK  CEREBRrM.  637 

of  the  pineal  body  ;  in  ;'/«/(/,  liy  Ihi'  anterior  commissure  and  the  anterior  ]iillars 
of  the  fornix  ;  and  behind,  by  the  posterior  eonnnissure,  tlie  orifice  of  the  atjueduet 
of  iSylvius,  and  the  pia  mater,  passing  from  tlie  upper  surface  of  the  pineal  body  to 
the  inferior  layer  of  the  velum  interpositum.  Its  floor  is  formed  by  the  bodies 
wliirh  till  the  interpeduncular  space  of  tiie  base  of  the  brain  and  tiie  su]ierior  sur- 
face of  the  crura  cereliri  at  their  origin  from  the  pons  Varolii.  The  structures  in 
the  inter|n'duncular  Space  are  named,  from  before  backward,  tlie  lamina  cinei'ea, 
tiie  tuber  cinereum,  the  infundibuium,  tlie  cor])ora  albicantia,  and  the  jKistcrior 
perforated  space. 

Commissures. — Stretching  across  tiie  ventricle  are  the  anterior,  middle,  and 
posterior  commissures.  The  anfcrior  commissure  is  situated  in  front  of  the  ante- 
rior crura  of  the  fornix.  It  is  comjiosed  of  white  matter  and  connects  the  two 
temporal  lobes  of  the  cerebrum.  The  iniddle  commissure  is  composed  almost 
entirely  of  gray  matter,  is  the  largest,  and  is  about  one-half  an  inch,  or  twelve 
millimeters,  in  width.  It  connects  the  optic  thalami,  and,  as  has  been  observed,  is 
frequentl}'  torn  across  in  the  dissection  of  the  brain.  The  jwsterior  commissure,  the 
smallest  of  the  three,  is  situated  in  front  of  and  beneath  the  pineal  liody,  and  above 
the  anterior  opening  of  the  aipieduct  of  Sylvius.  It  is  composed  of  white  matter, 
connects  the  optic  thalami,  and  probably  contains  decussating  fibers  derived  from 
various  sources. 

The  Foramina  of  Monro  are  the  orifices  of  communication  l)etween  the  lateral 
ventricles  and  the  third  ventricle.  Each  foramen  is  liounded  in  front  by  the 
corresponding  anterior  cms  of  the  fornix,  behind  by  the  optic  thalamus  and 
choroid  jilexus,  above  by  the  anterior  eras  of  the  fornix,  and  below  by  the  epen- 
dyma  reflected  from  the  optic  thalamus  to  the  anterior  cms  of  the  fornix.  The  two 
foramina  have  a  common  orifice  in  the  third  ventricle,  thus  forming  a  Y-shaped 
passage,  called  the  foramen  commune  anterius,  through  which  cerebro-spinal  fluid 
in  one  lateral  ventricle  may  enter  tlie  other  lateral  ventricle. 

Aqueduct  of  Sylvius. — At  the  posterior  extremity  of  the  third  ventricle,  and 
beneath  the  posterior  commissure,  is  .seen  the  anterior  orifice  of  the  aqueduct  of 
Sylvius,  or  iter  e  tertio  ad  quartum  ventriculum.  This  is  a  narrow  passageway 
about  three-fourths  of  an  inch,  or  two  centimeters,  in  length,  and  passes  beneath 
the  quadrigeminal  body  to  establish  a  communication  between  the  third  and  fourth 
ventricles.  It  is  lined  with  ependyma  which  is  continuous  with,  and  similar  to, 
that  lining  the  ventricles  which  it  connects.  Its  roof  is  formed  by  the  lamina 
quadrigemina,  a  plate  of  gray  matter  whicii  supports  the  corpora  quadrigemina. 
Its  floor  is  formed  by  the  tegmental  portions  of  the  crura  cerebri.  The  gray 
matter  in  its  floor  contains  the  nuclei  which  give  origin  to  the  third  and  fourth 
cranial  nerves. 


538  SURGICAL   ANATOMY. 

The  Optic  Thalami,  tlie  posterior  j)air  of  cerebral  ganglia,  are  two  oval  masses 
of  white  and  gray  matter.  They  are  convex  from  before  backward,  and  slightly  so 
from  side  to  side,  and  have  their  long  axis  directed  obliquely  from  before  backward 
and  from  within  outward.  They  lie  one  upon  each  side  of  the  third  ventricle, 
between  the  tails  of  the  caudate  nuclei,  and  rest  upon  the  crura  cerebri.  Each 
optic  thalamus  forms  a  large  portion  of  the  floor  of  the  body  of  the  lateral  ven- 
tricle, while  its  posterior  end  projects  into  the  descending  cornu  of  that  ventricle. 
Each  optic  thalamus  consists  of  two  extremities  :  an  anterior,  called  the  anterior 
tubercle,  which  forms  the  posterior  boundary  of  the  foramen  of  Monro,  and  a 
posterior,  called  the  pulvinar,  nr  posterior  tubercle.  The  upper  surface  of  each 
is  partly  free  and  partly  covered  by  the  choroid  plexus  of  the  lateral  ventricle,  the 
velum  interpositum,  and  the  lateral  border  of  the  body  of  the  fornix.  On  its 
upper  surface  is  situated  an  antero-posterior  groove,  called  the  sulcus  choroideus, 
for  the  attachment  of  the  velum  interpositum.  In  the  groove  between  the 
caudate  nucleus  and  the  optic  thalamus  lies  the  tasnia  semicircularis.  The  optic 
thalami  are  connected  by  the  middle  and  posterior  commissures  of  the  third 
ventricle.  Running  along  the  upper  border  of  each  optic  thalamus  from  behind 
forward  are  the  ]H'duncles  of  the  pineal  gland. 

Geniculate  Bodies. — Tlie  under  surface  of  the  posterior  extremity  of  each 
optic  thalamus,  which  forms  part  of  the  roof  of  the  middle  cornu  of  the  lateral 
ventricle,  presents  two  small  gray  eminences,  the  internal  and  external  geniculate 
bodies.  To  see  these  bodies  satisfactorily,  turn  the  brain  on  its  side  and  rai.se  the 
po.sterior  extremity  of  the  optic  thalamus.  The  internal  geniculate  bodies  are 
connected  internally  with  the  nates  of  the  corpora  quadrigemina  through  the 
medium  of  the  brachia,  and  externally  are  directly  continuous  with  the  optic 
tract. 

The  Pineal  Gland  or  Body,  Conarium,  or  Epiphysis  Cerebri,  is  a  small,  red- 
dish gray,  oval  body,  about  one-fourth  of  an  inch,  or  six  millimeters,  in  length. 
It  is  directed  forward  and  upward,  and  rests  upon  the  groove  between  the  ante- 
rior pair  of  the  corpora  quadrigemina  and  above  the  posterior  commissure  of  the 
third  ventricle.  From  the  base  of  the  pineal  body  a  white  cms,  or  peduncle, 
pas.ses  forward  u]ion  each  side  of  the  tliird  ventricle  and  along  the  upper  and 
inner  surface  of  tiie  ojitic  thalami  to  the  anterior  crura  of  the  fornix,  with  which 
the  peduncles  become  contiimous.  Posteriorly  they  are  joined  together  in  front 
of  the  base  of  the  pineal  body,  and  are  connected  with  the  posterioi'  commissure 
of  the  third  ventricle. 

Tlio  Corpora  Quadrigemina,  or  Optic  Lobes,  are  .situated  immediately  behind 
llie  tliird  ventricle,  and  are  composed  of  four  eminences.  These  are  arranged  in 
two  pairs:  an  iinteriiir  or  nppi'r,  the  larger  of  the  two,  and  called  the  nates,  and  a 


PLATE  GXXXIIl, 


Corpus  albicans 
Optic  tract 
Infundibulum 
Root  of  Olfactory  tract 


Optic   commissure 
Pituitary  body. 


Superior  peduncle  of  cerebellu 

Auditory  n. 
Pars  intermedia  of  Wrisberg(n.) 
Inferior  peduncle  of  cerebellum 


Abducent  n 
Glossopharyngeal  n 

Olivary  body 
Spinal  accessory  n. 

Anterior  pyramidal  tract  of  medulla  oblongata 


Medulla  oblongata 


Crus  cerebri 

External  geniculate  body 
nternal  geniculate  body 

Pulvinar  of  optic  thalamus 


Corpora 
quadrigemina 
Pathetic  n. 


Trifacial  n. 
Pons  Varolii 

-    Middle  peduncle 
:  cerebellum 

y Facial  n. 

Restiform  body 

Pneumogastric  n. 
Hypoglossal  n 


Anterior  root  of  first  cervical  n 


Posterior  root  of 
first  cervical  n. 


LATERAL  VIEW  OF  CORPORA  QUADRIGEMINA,  PONS,  AND  MEDULLA, 

539 


PLATE  CXXXIV. 


Septum  lucidum 
Anterior  pillars  of  fornix 
■  Peduncle    of  pineal  body 

Pineal  body 


Third  ventricle 

Caudate  nucleus 
/  Optic  thalamus 

\^  u         '  I  /Tenia  semicircularis 


Superior  peduncle  of 

cerebellum 
Superior  medullary  velum 
Middle  peduncle  of 

cerebellum  -^ 
Inferior  peduncle  of  ^ 

cerebelluii 


gitudinal  median 
sulcus 

Emmentia  teres 


Tuberculum  acusticu 

Trigonum  hypoglossi 

Ala  cinerea 

Posterior  median  fissure 

of  medulla  oblongata 

Funiculus  gracilis 


Conductor  sonorus 
StriiE  medullares 
Lateral  tract 
Funiculus  cuneatus 


THIRD  AND  FOURTH  VENTRICLES  AND  CORPORA  QUAORICEMINA, 

642 


THE  IXTERIOR    OF  THE  CEREBRUM.  5-l."> 

postcrinr  or  lower,  called  tin-  testes.  They  are  situated  uikui  a  layer  of  gray 
matter  known  as  the  lamina  quadrigemina,  whieh  overlies  tlie  aqueduct  of  Sylvius. 
They  give  off  anteriorly  four  liands  or  hraehia,  which  arc  composed  ol'  white 
matter  externally  and  gray  matter  internally.  The  brachia  of  the  nates,  or  supe- 
rior  brachia,  pass  under  the  internal  geniculate  bodies  into  the  optic  tracts.  The 
hraehia  of  the  testes,  or  inferioi-  bi-achia,  pass  below  and  external  to  the  brachia  of 
the  nates,  and  below  tlu'  internal  geniculate  bodies  leave  the  surface.  The  posterior 
(luadrigcniinal  bodies  or  testes  ai'e  cacli  connected  with  the  lieuusphere  of  the  ceri;- 
bellum  by  a  broad  band  of  white  matter,  the  superior  peduncle  of  the  ceivbcllum 
[l>niirxsus  e  cerebello  ad  testes). 

Dissection. — In  order  to  see  the  superior  cerebellar  peduncles  more  clearly, 
the  anterior  extremity  of  the  middle  lobe  of  the  cerebellum  should  be  lifted  sliglitly 
and  |)ushed  backward,  or,  better,  a  longitudinal  incision  should  be  carried  through 
the  middle  of  this  lobe,  and  each  half  displaced  laterally.  This  will  expose  these 
peduncles  clearly  and  also  show  the  fillet  and  the  valve  of  Yieussens. 

The  Superior  Peduncle  of  the  Cerebellum  (processus  e  cerebello  ad  testes)  con- 
nects the  hemisjjhere  of  the  cerebellum  with  the  opposite  hemisphere  of  the  cere- 
brum. It  passes  upward,  forward,  and  inward  along  the  side  of  the  anterior  part  of 
the  fourth  ventricle,  and  beneath  the  corpora  cjuadrigemina,  where  the  fibers  of  the 
two  peduncles  decussate  ;  beyond  the  corpora  quadrigemina,  along  with  the  teg- 
mental fibers  of  the  crura  cerebri,  the  fibers  of  each  peduncle  are  continued  to  the 
optic  thalamus  and  lenticular  nucleus  of  the  opposite  hemisphere  of  the  cerebrum. 
The  Valve  of  Vieussens,  the  anterior  or  .superior  medullary  velum,  is  a  tri- 
angular layer  of  white  matter,  narrow  in  front  and  broad  behind,  stretched  between 
the  superior  peduncles  of  the  cerebellum,  and  extending  from  the  anterior  extremity 
or  nodule  of  the  inferior  vermiform  process  of  the  cerebellum  to  the  corpora  quadri- 
gemina. It  forms  a  portion  of  the  roof  of  the  fourth  ventricle.  Along  the  middle 
line  of  the  upper  surface  is  a  longitudinal  ridge,  the  frenulum.  The  lower  half  is 
overlapped  by  the  lingula,  a  corrugated  lobule  of  gray  matter  jirolonged  from  the 
anterior  extremity  of  the  sujierior  vermiform  process.  The  trochlear  nerves  decus- 
sate witlnn  it,  and  emerge  from  its  dorsal  surface,  just  behind  the  inferior  <}uadri- 
geminal  bodies. 

The  fillet  is  a  small,  flat  band  or  bundle  of  nerve  fibers  situated  below  and 
external  to  tlie  superior  peduncle  of  the  cerebellum.  It  emerges  from  the  pons  at 
the  upper  limit  of  its  posterior  region,  and  appears  as  a  triangular  band  which  is 
situated  above  the  crus  cerebri  and  disappears  under  the  testis  and  brachium  of 
the  testis. 

Dissection'. — If  the  superior  and  inferior  vermiform  processes  of  the  cere- 
bellum  were  not    divided  longitudinally  when  exposing  the  valve  of  "\"icussens, 


544  SURGICAL   ANATOMY. 

they  should  be  divided  now,  and  each  lialf  reflected  laterally  to  expose  the  fourth 
ventricle. 

The  Fourth  Ventricle  is  a  quadrangular,  lozenge-shaped  space,  situated 
between  the  cerebellum  and  the  posterior  surface  of  the  medulla  oblongata  and 
pons  Varolii. 

The  roof  is  formed  anteriorly  by  the  valve  of  Vieussens  and  the  superior 
peduncles  of  the  cerebellum,  and  posteriorly  by  the  inferior  medullary  velum,  the 
inferior  vermiform  process  of  the  cerebellum,  the  choroid  plexus,  and  the  tela 
choroidea  inferior.  The  floor  is  formed  by  the  posterior  surface  of  the  medulla 
oblongata  and  pons  Varolii.  It  is  bounded  laterally  by  the  superior  peduncles  of 
the  cerebellum  above,  and  the  inferior  peduncles  of  the  cerebellum  below.  The 
ventricle  is  lined  by  the  ependyma  or  epithelial  wall  of  the  ventricles  of  the  brain. 
The  ventricle  presents  four  angles,  a  superior,  an  inferior,  and  two  lateral  (also 
called  the  lateral  recesses  of  the  ventricle).  The  widest  part  of  the  ventricle 
corresponds  to  the  interval  between  the  lateral  angles,  which  are  at  about  its 
middle. 

The  Tela  Choroidea  Inferior  is  that  part  of  the  pia  mater  on  the  posterior 
surface  of  the  medulla  oblongata  which  completes  the  posterior  part  of  the  roof  of 
the  fourth  ventricle.  It  contains  three  perforations :  the  foramina  of  Magendie, 
Key,  and  Retzius. 

The  foramen  of  Magendie  is  located  in  the  median  line  near  the  inferior 
angle  of  the  fourth  ventricle.  The  foramina  of  Key  and  Retzius  are  located  at  the 
lateral  recesses  of  the  ventricle.  By  way  of  these  openings  the  ventricle  communi- 
cates with  the  general  subarachnoid  space. 

The  two  choroid  plexuses  of  the  fourth  ventricle  are  also  derived  from  the 
pia  mater  by  the  intrusion  of  its  folded  edge  into  the  roof  of  that  cavity.  They 
extend  forward  from  the  posterior  angle  of  the  fourth  ventricle  near  the  median 
line  for  a  short  distance,  and  then  diverge  to  reach  the  lateral  recesses  of  the  ven- 
trick'. 

The  fourth  ventricle  communicates  with  the  third  ventricle  by  way  of  the 
aqueduct  of  Sylvius,  and  with  the  central  canal  of  the  spinal  cord  through  an 
opening  in  the  inferior  angle  which  is  dilated  and  is  called  the  ventricle  of 
Arantlus. 

The  flof)r  of  tlic  fourth  vuntrick;  is  its  most  important  part,  for  the  reason  that 
tlie  nuclei  of  most  f)l'tlu'  cranial  nerves  are  situated  there.  It  is  composed  chiefly 
of  gray  matter  continuous  willi  the  gray  matter  of  the  spinal  cord.  Occupying 
the  middle  line  of  the  fliKir  of  the  fourth  ventricle  is  the  median  longitudinal 
fissure.  It  extends  from  the  posterior  orittceof  the  aqueduct  of  Sylvius  to  the  pos- 
terior or  inferior  angle  of  the  ventricle,  which  is  at  the  point  of  divergence  of  the 


II— :i5 


PLATE  CXXXV. 


Head  of  caudate  nucleus 
Anterior  limb  of  internal  capsule 
Posterior  limb  of  internal  capsule 
Lenticular  nucleus 
External  capsule 
Claustrum 
Island  of  Reil 


Rostrum  of  corpus  callosum 
Septum  lucidunn 
,Optic  thalamus 

Anterior  cornu  of  right 
lateral  ventricle 
Anterior  pillar  of  fornix 
Tenia  semicircularis 


Tail  of  caudate  nucleus 

Choroid  plexus' 
Posterior  pillar  of  fornix' 
Hippocampus  major' 


Pia  mater  in 
hippocampal  fissure 
Posterior  cornu  of 
right  lateral  ventricio 
Velum  interpositum 
Body  of  fornix 
Spleniuni  of  corpus  callosum 


TRANSVERSE  SECTION  OF  CEREBRUM. 
54G 


THE  INTERIOR    OF  THE   CEREBRUM.  547 

restiibnn  Ijodics  (if  the  inedulla.  This  fissure  is  coiitinudus  helow  with  tiie  central 
canal  of  the  spinal  cunl.  This  portion  of  the  fourth  ventricle  has  received  the 
name  of  calamus  scriptorius  because  of  the  resemhlance  of  the  longitudinal  fis- 
sure and  the  diverging  posterior  pyramids  and  restiform  bodies  to  the  point  of  a 
pen.  Immediately  to  each  side  of  the  median  furrow  is  a  longitudinal  ridge, 
the  eminentia  teres.  Crossing  this  eminence  in  the  lower  half  of  the  ventricle  are 
bands  of  white  matter,  the  auditory  strite  or  striae  acusticae.  To  the  outer  side  of 
the  eminentia  teres  and  anterinr  to  tlie  auditory  striie  is  a  depressed  area,  the  svpe- 
rior  fovea,  while  behind  the  auditory  stria^  and  to  the  outer  side  of  the  eminentia 
teres,  are  two  furrows  so  united  as  to  form  an  invci'ted  V,  the  iitfcrior  fovea;  the 
floor  of  the  inferior  fovea  is  known  as  the  ala  cinerea. 

The  trigonum  hypoglossi  is  the  area  of  the  floor  of  the  fourth  ventricle 
bounded  bj^  the  longitudinal  fissure,  stria3  acusticfe,  and  inferior  fovea,  and  covers 
the  nucleus  of  the  hyi^glossal  nerve.  The  tuberculum  acusticum  is  the  triangular 
area  situated  between  the  inferior  fovea  and  the  clava  of  the  funiculus  gracilis,  and 
extending  forward  under  the  striise  acustica;. 

In  front  of  the  superior  fovea  and  external  to  the  eminentia  teres  is  a  small 
eminence  of  dark  gray  matter,  the  locus  caeruleus.  Prolonged  forward  from  the 
locus  caeruleus,  at  the  side  of  the  eminentia  teres  and  extending  to  the  upper  end  of 
the  floor  of  the  ventricle,  is  a  thin  streak  of  dark  gray  matter,  the  taenia  violacea. 
The  locus  cseruleus  and  taenia  violacea  are  produced  by  the  substantia  ferruginea, 
whose  dark  color  is  seen  through  the  overlying  white  matter.  The  substantia 
ferruginea  is  the  dark,  pigmented  mass  seen  in  sections  of  the  upper  part  of  the 
floor  of  the  fourth  ventricle.  The  ependyma  lining  the  fourth  ventricle  is  contin- 
uous through  the  acjueduct  of  Sylvius  with  that  lining  the  third  ventricle. 

Dissection. — Next  complete  the  dissection  of  the  cerebrum  by  making  hori- 
zontal sections  of  the  corpora  striata  and  optic  thalami,  carrying  the  incisions 
through  to  the  external  or  lateral  surface  of  the  hemisphere.  This  will  expose  the 
caudate  nucleus,  the  internal  capsule,  the  lenticular  nucleus,  the  external  capsule, 
the  claustrum,  and  the  island  of  Reil  from  within  outward  in  the  order  named. 

The  Caudate  Nucleus,  or  intra-ventricular  jjortion  of  the  corpus  striatum,  is 
the  more  anterior  of  the  gray  basal  ganglia,  and  has  been  described. 

The  Internal  Capsule  lies  external  to  and  behind  the  caudate  nucleus,  and 
separates  the  caudate  from  the  lenticular  nucleus,  and  the  lenticular  nucleus  from 
the  optic  thalamus.  The  internal  capsule,  composed  of  white  matter  and  some- 
what crescentic  or  angular  in  shape,  consists  of  a  genu  and  two  limbs,  an 
anterior  and  a  posterior.  The  anterior  limb,  named  by  Spitzka  the  caudo-lenticular 
portion,  intervenes  between  the  caudate  and  lenticular  nuclei.  The  poaterior  limb, 
named  by  the  same  author  the  thalamo-lenticular  portion,  intervenes  between  the 


648  SURGICAL  ANATOMY. 

optic  thalamus  and  the  lenticular  nucleus.  The  g(;nu,  the  point  where  the  capsule 
presents  the  greatest  angularitj',  is  opposite  the  interval  between  the  caudate 
nucleus  and  the  optic  thalamus. 

Through  the  internal  capsule  the  nerve  fibers  pass  in  their  course  from  the 
gray  matter  of  the  cortex  of  the  cerebrum  and  caudate  and  lenticular  nuclei  to 
the  crus  cerebri,  which  transmits  these  fibers  from  the  cerel>rum  to  the  pons, 
medulla  oblongata,  and  spinal  cord.  In  addition  to  these  fibers  the  internal  cap- 
sule contains  fibers  from  the  cerebral  cortex  to  the  optic  thalamus. 

The  anterior  third  of  the  internal  capsule  contains  the  fibers  from  the  cortex 
of  the  prefrontal  lobe,  or  silent  region,  the  middle  third,  the  filjcrs  from  the  motor 
or  Rolandic  area  of  the  cortex  of  the  cerebrum,  and  the  posterior  third,  the  sensory 
fibers  from  the  occipital  and  temporal  lobes. 

Destruction  of  the  anterior  two-thirds  of  the  posterior  segment  of  the  internal 
capsule,  which  occurs  in  many  cases  of  apoplexy,  results  in  motor  paralj'sis  of  the 
opposite  side  of  the  body.  This  paralj'sis  is  diffuse,  and  not  confined  to  a  group 
of  muscles,  as  in  lesions  of  the  cerebral  cortex,  while  destruction  of  the  poste- 
rior ])art  of  the  posterior  limb  of  the  internal  capsule  results  in  loss  of  sensation 
of  the  opposite  side  of  the  body.  A  small  hemorrhage  in  the  capsule  will  cause 
paralysis  of  that  part  of  the  opposite  side  of  the  body  supplied  by  the  fibers 
compressed  by  the  clot  of  l„)lood. 

The  Lenticular  Nucleus,  or  exti'aventricular  portion  of  the  corpus  striatum, 
is  larger  than  the  caudate  nucleus,  is  oval  in  form,  and  lies  behind  and  to  the 
outer  side  of  the  caudate  nucleus.  It  is  separated  from  the  caudate  nucleus  by  the 
anterior  limb  and  genu  of  the  internal  capsule,  and  from  the  optic  thalamu-s  hy  the 
posterior  limb  of  the  internal  capsule. 

The  external  capsule  is  a  band  of  white  matter  which  lies  to  the  outer  side 
of  the  lenticular  nucleus,  and  joins  the  internal  cap.sule  below  the  lenticular 
nucleus. 

The  claustrum  is  a  thin  la3'er  of  gra}'  matter,  laying  to  the  outer  side  of  the 
external  capsule. 

The  Island  of  Reil,  previously  described,  is  external  to  the  claustrum,  and 
separated  from  it  l)y  a  layer  of  white  matter. 

White  Matter  of  Cerebrum. — In  the  dissection  of  the  cerebrum,  which  will 
be  completed  when  the  crura  cerebri  have  been  traced  from  the  upper  border  of 
the  jions  to  each  hemisphere,  it  should  lie  notod  that  the  white  matter  of  the  cere- 
brum is  compiiscil  of  three  systems  or  sets  of  medullated  nerve  fibers,  the 
ascending  or  peduncular,  the  transverse  commissural,  and  the  longitudinal  com- 
missural. The  ascenilliirj  or  peduncular  fibers  are  those  fibers  of  the  crura  cerebri 
M'hiili,  ill  diverging  to  reach  the  nerve  cells  of  the  cerebral  cortex,  form  the  corona 


THE   rO.\S    VAROLII.  549 

radinta,  so  called  on  account  of  the  crown-like  radiation  of  its  fibers.  The  trans- 
verse commissural  fibers  include  the  fibers  of  tlic  corpus  callosum  and  the  anterior 
and  posterior  commissures  of  the  third  ventricle.  The  longitudinal  commissural 
fibers  include  the  fibers  of  the  fornix,  tlie  strife  longitudinales  of  the  corpus 
callosum,  tlie  tienia  >>emicircu]aris,  tihers  in  the  gyrus  fornicatvis  and  gyrus  hippo- 
campi, and  tlie  peduncles  of  the  iiineal  body.  They  also  include  the  associating 
fibers:  tliose  fibers  which  connect  the  cells  of  neighboring  and  of  more  distant  con- 
volutions. 

THE  PONS  VAROLII. 

DissECTiox. — Having  completed  tlie  dissection  of  the  cerebrum,  excepting  the 
tracing  of  the  crura  cerebri,  turn  the  l)rain  so  as  to  expose  the  base,  and  .study  the 
pons,  then  the  medulla  oblongata,  and  lastly  the  cerebellum. 

The  Pons  Varolii,  or  Tuber  Annulare,  is  that  division  of  the  brain  through 
the  medium  of  wliicli  tlie  other  three  divisions  of  the  brain  are  united.  It  is  con- 
nected with  the  cerebrum,  above,  by  the  crura  cerebri,  or  peduncles  of  the  cere- 
brum ;  with  the  cerebellum,  behind,  by  the  middle  peduncles  of  the  cerebellum  ; 
and  with  the  medulla,  below,  by  tlie  fibers  of  the  jayramidal  tract  of  tlie  medulla 
oblongata.  It  is  situated  behind  the  crura  cerebri,  in  front  of  thq  medulla  oblon- 
gata, between  and  below  the  hemispheres  of  the  cerebellum,  and  between  the 
posterior  portion  of  the  temporo-sphcnoid  lobes  of  the  cerebrum.  In  the  cranial 
cavity  it  lies  below  the  level  of  the  superior  occipital  foramen  of  the  tentorium 
cerebelli,  and  rests  upon  the  basilar  process  of  the  occipital  bone  and  the  posterior 
surface  of  the  body  of  the  sphenoid  bone.  It  is  quadrangular  in  shape,  and  is 
composed  chiefly  of  white  matter,  the  fillers  of  which  are  arranged  transversely 
and  longitudinally.  It  presents  two  surfiaces,  an  anterior  and  a  posterior.  The 
anterior  surface  is  markedly  convex  from  side  to  side,  and  slightly  so  from  before 
backward,  and  measures  transversely  altout  one  and  one-half  inches,  or  four  centi- 
meters, and  is  about  one  inch,  or  twenty-five  millimeters,  in  length.  The  anterior 
surface  is  marked  along  the  middle  line  by  a  groove,  which  is  broader  in  front  than 
behind,  and  lodges  the  basilar  artery.  The  anterior  surface  presents  two  borders, 
an  upper  and  a  lower.  The  upper  border,  the  longer,  is  convex,  and  arches 
beneath  the  crura  cerebri.  The  lower  border  is  almost  straight,  and  is  separated 
from  tlie  medulla  oblongata  by  a  transverse  groove.  The  posterior  surface  is  slightly 
concave  from  side  to  side,  and  forms  part  of  the  floor  of  tlie  fourth  ventricle. 
From  the  side  of  the  pons  the  trifacial  or  fifth  cranial  nerve  is  seen  emerging. 

In  coronal  sections  the  pons  can  be  divided  into  an  anterior  or  ventral  region, 
and  a  posterior  or  tegmental  region.  The  anterior  region  of  the  iwns  is  composed 
of  transverse  and  longitudinal  fibers.     The  superficial  transverse  fibers  of  the  ante- 


550  SURGICAL   ANATOMY. 

rior  region  of  the  pons  pass  obliquely  outward  and  l^aekward  to  the  hemispheres 
of  tlie  cerebellum,  forming  the  middle  peduncles  of  the  cerebellum.  The  deep 
transverse  fibers  of  the  anterior  region  of  the  pons  are  decussating  filjcrs,  wiiicli 
are  crossing  in  the  pons  in  passing  from  the  cerebellar  hemisphere  of  one  side  to 
the  cerebral  hemisphei-e  of  the  opposite  side.  The  longitudinal  fibers  are  more 
deeply  situated  than  the  superficial  transverse  fibers,  and  are  separated  into 
bundles  by  the  deep  transverse  fibers.  They  are  the  fibers  of  the  pyramidal 
tracts  of  the  medulla  oblongata,  passing  upward  to  enter  the  crustte  of  the  crura 
cerebri. 

In  the  posterior  or  tegmental  region  of  the  pons  the  chief  structures  observed  are 
the  tract  of  the  fillet,  which  is  seen  nearest  the  anterior  region,  the  formatio  retic- 
ularis, the  posterior  longitudinal  bundle,  and  the  superior  olivary  nucleus.  This 
region  of  the  pons  also  contains  the  nuclei  of  the  sixth  and  seventh  cranial  nerves, 
and  a  part  of  the  nucleus  of  the  eighth  cranial  nerve.  While  the  importance  of 
these  nuclei  has  been  clearly  proved  by  cliiucal  experience  in  cases  of  paralysis 
caused  by  hemorrhage  occurring  within  the  substance  of  the  pons,  as  well  as  by 
microscopic  investigation,  they  are  not  macroscopically  visible. 

Hemorrhage  into  the  pons  is  u-suallj'  followed  by  coma  and  sudden  death,  par- 
ticularly if  the  hemorrhage  is  extensive,  or  if  the  blood  escapes  into  the  fourth 
ventricle.  The  decussation  of  the  trifacial  and  the  facial  nerves  takes  place  within 
the  pons  ;  if,  therefore,  a  lesion — as,  for  exami)le,  a  small  lieraorrhage — occur  above 
the  point  of  the  crossing  of  the  fibers  of  the  facial  nerve,  paralysis  of  the  face  and 
body  on  the  side. opposite  the  lesion  will  occur;  while  if  the  lesion  be  immediately 
below  the  point  of  crossing,  the  paralysis  of  the  face  will  be  upon  the  side  of  the 
lesion  and  the  hemiplegia  upon  the  side  opposite  to  the  le.sion,  thus  giving  rise  to 
the  condition  known  as  crossed  hemiplegia.  Nerve  fibers  from  the  motor  cortical 
area  for  speech  run  through  the  pons,  and  may  be  involved  in  a  lesion  of  the  pons, 
thus  giving  rise  to  aphasia. 

The  Crura  Cerebri,  or  Peduncles  of  the  Cerebrum,  are  two  large  round 
bodies  of  white  matter,  about  three-fourths  of  an  inch,  or  two  centimeters,  in 
length,  and  broader  in  front  than  behind.  They  emerge  from  the  upper  border  of 
the  pons,  whence  they  pass  outward  and  forward  to  enter  the  under  part  of  the 
hemispheres  of  the  cerebrum.  They  pass  through  the  superior  occipital  foramen 
in  company  witli  the  superior  peduncles  of  the  cerebellum,  the  basilar  artery, 
and  the  ocuio-inotor  and  pathetic  nerves.  '  Crossing  the  lower  surface  of  the 
crura  just  before  they  enter  the  hemispheres  of  the  cerebrum,  and  adherent  to 
them,  ai'c  the  ()]>tic  tracts,  while  in  rclafioii  with  their  inner  borders  are  the 
oculii-MKitor  nci'vcs,  and  with  their  nuter  miirgiiis,  tjie  ])atiietic  nerves. 

Dissection. — Divide  one  of  (lie  crura  cerebri  transver.sely,  and  a   nuekais  of 


PLATE  CXXXVI, 


Pituitary  body 
Optic  n 
Tuber  cinereum 
Corpora  albicantia 
3rd  cranial  n. 


4th  cranial  n. 

Motor  root  of  5th  cranial  n 

Sensory  root  of  5th 

cranial  n. 


Middle  peduncle  of 

cerebellum 


Anterior  median  fissure 


Pyramidal  tract  of  medulla 


Olivary  body 
I  2th  cranial  n 


Decussation  of  pyramids 


Optic  tract 
Crus  cerebri 

Optic  thalamus 


External  geniculate  body 

nternal  geniculate  body 
Pons  Varolii 


*.  -^^^^ 

6th  cranial  n 

iffifr-^ 

7th  cranial  n. 

ff  Jjl^^^r                    ^^^  rTf^niril  n 

^ loth  cranial  n. 

^ 

1 th  cranial  n. 

Lateral  tract 


ngata 


PONS,  MEDULLA,  AND  SUPERFICIAL  ORIGINS  OF  CRANIAL  NERVES. 


nf)'? 


THE  MEDULLA    OB  LONG  ATA.  553 

gray  matter — the  locus  nigcr,  or  substantia  nigra — will  be  seen  in  the  interior  of 
the  cms.  Through  tlie  medium  of  this  nucleus  the  crus  ccrel)ri  is  divided  into  an 
upper  or  posterior  portion  and  a  lower  or  anterior  jiortion.  'I'he  upper  oi-  jiosterior 
porlidu  is  kniiwu  as  the  tegnientuui,  and  the  lower  or  nulerior  [lortion  as  the 
crusta. 

The  tegmentum  of  the  crus  cerebri  is  composed  largely  of  the  longitudinal 
fibers  of  the  tegmental  region  of  the  pons,  which  proceed  from  the  lateral  tract 
and  posterior  pyramids  of  the  medulla  oblongata ;  it  also  receives  the  fibers  of  the 
superior  peduncle  of  the  cerebellum.  The  tegmental  fibers  of  the  crus  cerebri  are 
sensory,  and  enter  the  hemisphere  of  the  cerebrum  below  and  through  the  optic 
thalamus,  beyond  which  they  form  jiart  of  the  corona  i-adiata.  The  tegmen- 
tum contains  two  nuclei,  the  siihlluildinir  hoihj  and  the  tegmental  or  red  nucleus. 
The  aihuixture  of  gray  and  white  matter  of  the  tegmentum  forms  the  formafio 
reticultiri.'t. 

The  crusta  is  composed  chiefly  of  the  longitudinal  fibers  of  the  anterior 
region  of  the  pons,  which  proceed  from  the  anterior  pyramids  of  the  medulla.  The 
fibers  of  the  crusta  are  motor,  and  enter  the  hemisphere  through  the  internal  cap- 
sule, beyond  which  they  form  a  part  of  the  corona  radiata.  Tlie  inner  one-fifth  of 
the  crusta  contains  fillers  which  are  passing  to  the  pons  from  the  prefrontal  lobe. 


THE  MEDULLA  OBLONGATA. 

The  Medulla  Oblongata,  or  Bulb,  the  upper  continuation  of  the  spinal  cord, 
begins  at  the  decussation  of  the  pyramids  or  the  upper  border  of  the  atlas,  and 
extends  to  the  lower  border  of  the  pons  Varolii,  being  not  cjuite  one  and  one-half 
inches,  or  3.5  centimeters,  in  length.  It  increases  in  -width  from  below  upward, 
and  just  below  the  2:)ons  it  is  about  three-fourths  of  an  inch,  or  two  centimeters, 
wide.  Its  anterior  or  ventral  surface  rests  partlj'  upon  tlie  basilar  portion  of  the 
occipital  bone,  and  its  posterior  or  dorsal  surface  is  directed  toward  the  vallecula 
of  the  cerebellum,  which  lodges  part  of  the  medulla.  The  anterior  surface  pre- 
sents, in  the  median  line,  the  anterior  median  fissure,  which  is  the  continuation 
upward  of  the  anterior  median  fissure  of  the  spinal  cord,  which  fissure  is,  however, 
interrupted  by  white  fibers  crossing  from  one  side  to  the  other  and  forming  the 
decussation  of  the  pyramids.  On  its  posterior  aspect,  for  one-half  the  length  of 
the  medulla,  is  situated  the  jiosterior  median  fissure  or  sulcus,  the  continuation  of 
the  corresponding  fissure  of  the  spinal  cord. 

The  medulla  oblongata,  like  the  spinal  cord,  is  divided  into  an  anterior, 
a  lateral,  and  a  posterior  area.  The  anterior  area  is  occupied  by  tlie  anterior  pyra- 
mids.    The  lateral  area  is  occupied  by  the  olivary  Imdy  and    the  lateral  culumn. 


554  SURGICAL  AXATOMY. 

The  jiosterior  area  contains  tliu  funit-ulus  of  Rolando,  funiculus  cuncatus,  and 
funiculus  gracilis,  and  in  its  uj)})cr  }inrtinn  is  the  restiforni  liody. 

The  Anterior  Pyramids,  or  Pyramids  of  the  Medulla  Oblongata,  are  situ- 
ated between  the  anterior  median  and  antero-lateral  fissures.  They  are  larger 
above,  but  are  somewhat  constricted  and  roun(]ed  wliere  they  disajjpear  beneath 
the  sui^erficial  transverse  fibers  of  the  pons.  On  separating  the  anterior  pyramids 
below,  bundles  of  fibers  will  be  .seen  decussating  across  the  anterior  median  fissure. 
This  decussation  is  produced  by  the  innermost  fibers  of  the  pyramids,  which  are 
derived  from  the  lateral  or  crossed  pyramidal  tracts  of  the  spinal  cord,  and  have 
reached  the  surface  of  the  medulla  oljlongata  at  this  jioint  by  cutting  through  the 
anterior  horn  of  the  gray  matter  of  the  spinal  cord,  and  pusliing  aside  the  anterior 
pyramid..  The  outermost  fibers,  wliicli  form  the  smaller  number  of  fibers  of  the 
pyramid,  do  not  decussate,  and  continue  downward  as  the  direct  pyramidal  tract 
of  the  spinal  cord  ;  the.se  fibers  decussate  in  the  anterior  or  white  commis.sure  of 
the  spinal  cord.  The  decussation  of  the  pyramids  of  the  medulla  explains  the 
fact  that  in  disease  or  injury  of  the  motor  cortex  of  the  lirain  the  paralysis  is 
found  on  the  side  of  the  lioily  opposite  to  tlie  lesion  in  the  brain. 

The  continuation  of  the  anterior  ground  bundle  of  the  spinal  cord  is  not  seen 
in  the  anterior  ai'ea  of  the  medulla  oT)longata,  as  the  fibers  of  that  tract  are  de- 
pressed from  the  surface  by  the  decussating  bundles  of  the  crossed  pyramidal  tract. 

The  Olivary  Body  is  an  oval  prominence  on  the  medulla  oblongata,  situated 
to  the  outer  side  of  the  anterior  pyramid.  It  is  separated  from  the  anterior 
pyramid  by  a  narrow  longitudinal  groove,  the  hypoglossal  sulcus,  or  antero-lateral 
furrow  of  the  medulla,  which  is  continuous  with  the  antero-lateral  fissure  of  the 
spinal  cord.  The  olivary  bodj-  is  limited  posteriori}^  by  the  post-olivary  sulcus. 
Like  the  anterior  pyramid,  it  is  broader  above  than  below.  It  is  separated  from 
the  piiiis  l)y  a  deep  groove,  and  is  aljout  one-half  an  inch,  or  twelve  to  fifteen 
millimeters,  in  length.  Emerging  from  the  hypoglossal  sulcus  or  antero-lateral 
furrow  arc  the  roots  of  the  hypoglossal  nerve.  .Vrching  below  and  over  the  olivary 
body,  and  emerging  from  tlie  anterior  meilian  and  antero-lateral  fissures,  several 
white  bundles  are  seen — the  superficial  arciform  fibers — which  enter  the  restiform 
body  of  the  same  side.  If  an  r}blique  incision  be  carried  through  the  olivary 
body,  there  will  !>(_■  reveaU'il  in  its  interinr  a  nucleus  of  gray  matter,  the  corpus 
dentatum  "f  the  (jlivary  liody.  This  nueleus  is  arranged  in  the  form  of  a 
hdlliiw  ea|i-ule,  and  presents  a  com-dluled  outline  jiartly  incomplete  at  its  inner 
side.  Tiiniugji  this  0]ien  part  of  the  (•a})sule  jia.sses  a  bundle  of  white  fibers,  the 
peduncle  of  the  olivary  body. 

'I'lie  Lateral  Tract  of  the  Medulla  Oblongata  is  apparently  the  upward  exten- 
sion of  tlu^   lateral    colunin  of  tjie  spinal   vovd,  Init  it  does  not  contain  tlie  crossed 


PLATE  CXXXVIl, 


Septum  lucidum 
Anterior  pillars  of  fo 
Peduricle    of  pineal  body 

Pineal  body 


Third  ventricle 

Caudate  nucleus 

Optic  thalamus 
/  /Tenia  semicircularis 


estes 

ngitudinal  median 
sulcus 

Eminentia  teres 


Superior  peduncle  of 

cerebellum 
Superior  medullary  velum 
Middle  peduncle  of 

cerebellum 
Inferior  peduncle  of 

cerebellum 


Tuberculum  acusticu 
Trigonum  hypoglossi 
Ala  cinerea 


Posterior  median  fissure 

of  medulla  oblongata'' 


Funiculus  gracilis 


Conductor  sonorus 
Striae  medullares 
Lateral  tract 
Funiculus  cuneatus 


THIRD  AND  FOURTH  VENTRICLES  AND  CORPORA  QUADRICEMINA. 

55G 


THE  MEDULLA   OBLONGATA.  557 

in-ramidal  tract  of  tlie  cord,  wliicli  ciitrrs  (lie  ]iyrauiiilal  tract  of  the  medulla 
uMongata,  and  the  direct  cerebellar  tract  of  the  cord  leaves  it  to  enter  the  resti- 
form  hody.  It  is  lioiuided  in  front  by  the  anierodateral  furrow,  and  behind  by  the 
posterudateral  hirrow.  Emerging  from  the  antii-odateral  hirrow  or  hypoglossal 
sulcus  are  the  roots  of  the  hypoglossal  nerve,  and  from  the  postero-lateral  furrow 
the  roots  of  the  glosso-pharyngeal,  pneumogastric,  and  spinal  accessory  nerves 
emerge.  As  it  ascends,  the  lateral  tract  of  the  medulla  becomes  less  marked, 
the  greater  jiurtion  of  it  passing  beneath  the  olivary  body. 

Dissection. — To  examine  satisfactorily  the  remaining  portion  of  the  medulla 
oblongata,  lift  it  out  from  the  interval  between  the  hemispheres  of  the  cerebellum, 
and  displace  it  forward,  thus  exposing  the  posterior  surface  of  the  medulla,  as  well 
as  that  portion  of  the  floor  of  the  fourth  ventricle  formed  by  the  medulla. 

The  Funiculus  of  Rolando,  which  lies  posterior  to  the  lateral  tract  and  on  the 
outer  side  of  the  funiculu.s  cuneatus,  is  the  u])ward  continuation  of  a  mass  of  gray 
matter — the  substantia  gelatinosa — which  caps  tlie  posterior  cornu  of  the  gray 
matter  of  the  spinal  conh  This  funiculus  presents  an  enlargement  on  a  level  with 
the  lower  end  of  the  olivary  body,  called  the  tubercle  of  Rolando. 

The  Funiculus  Cuneatus  lies  between  the  funiculus  of  Kolando  and  the  poste- 
rior median  column  or  posterior  pyramid.  It  is  the  widest  and  thickest  of  the 
columns  of  the  medulla.  Upjiosite  the  clava  of  the  funiculus  gracilis  it  forms  a 
prominence  called  the  cuneate  tubercle. 

The  Posterior  Pyramid,  or  Funiculus  Gracilis,  the  continuation  upward  of 
the  posterior  median  column  of  the  spinal  cord,  lies  immediately  to  the  outer  side 
of  the  posterior  median  fissure.  At  the  lower  end  of  the  fourth  ventricle  it  swells 
out  and  forms  a  prominence,  called  the  clava.  The  cuneate  tubercle  and  the 
clava  are  produced  by  accumulations  of  gra}'  matter  known  respectively  as  the 
cuneate  and  gracile  nuclei ;  almost  all  the  fibers  of  the  funiculus  cuneatus  and  funic- 
ulus gracilis  terminate  in  these  nuclei. 

The  Restiform  Body  appears  to  be  formed  l)y  the  funiculus  gracilis,  the  funic- 
ulus cuneatus,  and  the  funiculus  of  Rolando,  passes  outward  and  upward,  and 
then  enters  the  cerebellum,  forming  the  inferior  peduncle  of  the  cerebellum.  Since 
tlie  fibers  of  the  funiculus  cuneatus  and  funiculus  gracilis  terminate  in  the  cuneate 
and  gracile  nuclei,  they  can  not,  therefore,  .strictly  speaking,  be  said  to  be  directly 
continued  into  the  restiform  bodies.  The  following  are  the  more  important  of  the 
sources  from  which  the  fibers  of  the  restiform  body  are  derived  :  "(1)  From  the 
lateral  column  of  the  spinal  cord,  through  the  direct  cerebellar  tract ;  (2)  from  the 
convoluted  nucleus  of  the  olivary  body  of  the  opposite  side ;  (3)  from  the  gracile 
and  cuneate  nuclei  of  the  opposite  side  ;  (4)  frcjui  the  gracile  and  cuneate  nuclei  of 
the  same  side  "  (Cuimingliam).     By  the  divergence  of  the  restiform  bodies  the  lateral 


558  SURGICAL  AXATOMY. 

boundaries  of  the  lower  part  of  the  fourth  ventricle  are  formed,  while  the  apex  of 
the  lower  triangle  of  the  ventricle  is  situated  at  the  point  of  separation  of  the  two 
clava\  This  divergence  exposes  the  gray  matter  of  the  interior  of  the  meduHa, 
which  forms  tlie  floor  of  the  lower  portion  of  the  fourth  ventricle  and  is  continuous 
with  the  gray  matter  of  the  spinal  cord. 

Recapitulation. — Review  the  parts  seen  in  studying  the  medulla  from  before 
backward.  They  are  ;  The  anterior  median  fissure,  the  anterior  pyramid,  the  hypo- 
glossal or  antero-lateral  fissure  with  the  roots  of  tlie  hypoglossal  nerve,  the  olivary 
body,  containing  the  corpus  dentatum,  the  post-olivary  sulcus,  the  lateral  tract,  the 
postero-lateral  fissure  with  the  roots  of  the  glosso-pharyngeal,  pneumoga.stric,  and 
spinal  accessory  nerves,  the  funiculus  of  Rolando  and  its  tubercle,  the  funiculus 
cuneatus  with  the  cuneate  tubercle,  the  funiculus  gracilis  with  the  clava,  and  the 
posterior  median  fissure. 

Function. — The  medulla  is  described  Ijy  Ranney  as  "  the  true  nerve  center 
of  animal  life."  Several  of  the  cranial  nerves  have  their  primary,  deep,  or 
central  origin  whollj'  or  in  j^art  in  the  medulla.  Some  of  the  centers  contained 
within  the  medulla  are  the  respiratory,  the  vaso-motor,  the  cardio-inhibitory,  the 
diabetic,  and  a  salivary  center. 


THE  CEREBELLUM. 

Position,  Size,  and  Connections. — The  cerebellum,  or  little  brain,  lies  beneath 
the  occipital  lobes  of  the  cerebrum,  behind  the  j^ons,  and  above  and  upon  both 
sides  of  the  medulla  oblongata.  It  occupies  the  inferior  occipital  fossae,  and  lies 
beneath  the  tentorium  cerebelli,  which  separates  it  from  the  ccrelirum. 

The  surface  of  the  cerebellum,  like  tliat  of  the  cerebrum,  is  composed  of  gray 
matter,  which  is  darker  in  color  in  the  cerebellum,  and  arranged  in  laminse  instead 
of  in  convolutions.  The  cei'ebellum  measures  from  three  and  one-half  to  four 
inches,  or  from  nine  to  ten  centimeters,  in  its  transverse  diameter,  from  two  to  two 
and  one-half  inches,  or  from  five  to  six  centimeters,  in  its  antero-posterior  diameter, 
and  aliout  two  inches,  or  five  centimeters,  in  its  vertical  diameter  at  the  thickest 
part.  It  is  attached  to  the  cerel)rum  by  tlie  superior  peduncles,  to  the  pons  by  the 
middle  peduncles,  and  to  the  nu'dulla  oljlongata  by  the  inferior  peduncles  of  the 
cerebellum. 

Lobes. — Tlie  cerebellum  consists  of  two  liemispheres  and  a  central  lobe, — the 
vermiform  process,  or  vermis, — through  the  medium  of  which  the  hemispheres  are 
niiitcil.  The  hemispheres  are  separateil  inferiorly  liy  a  comparatively  wide  and 
di(  p  median  groove,  tlu'  vallecula,  nr  valley,  wliich  is  occujiied  in  great  jiart  by 
tlie  nie<lulla  ol)l()ngata  ;    the  inlerior  vermiform  jirocess  of  tlie  cerebellum  also  jiro- 


PLATE  CXXXVIll. 


Pons  Varol 
Fourth  vontricle 

Inferior  peduncle(cut) 
Middle  pedunci 
Pyrar-'-' 

Tuber  valvulae 


Nodule 
Uvula 
Amygdala 
Biventral  lobe 
Flocculus 
Slender  lobe 

Posterior  inferior 
e 


Great  horizontal 
fissure 


INFERIOR   SURFACE. 


Declive 
Folium  cacuminis 
Gri.at  horizontal  fissure 


Nates 
Testes 
Superior  medullary  velum 

Lobulus  centralis 
Anterior  crescentic  lobule 
Quadrate  lobe 


Internal  geniculate  body 
Pineal  body  ' 
Frenulum  veli 
4th  cranial  n 
Superior  peduncle 
Posterior  crescentic  lobule 

Culmen 
Sulcus  cerebelli 
superior 


r 


ostenor  superior 
lobe 


SUPERIOR  SURFACE. 

INFERIOR  AND  SUPERIOR  SURFACE  OF  CEREBELLUM. 
5G0 


THE   CEREBELLUM.  oGl 

jcets  into  tliu  vallev.  Tlie  hemispheres  are  separated  in  t'nmt  hy  a  notch,  tlic  in- 
cisura  cerebelli  anterior,  wliii-li  lodges  the  inferior  pair  of  t-orpora  (|uadrii;(  niiua 
and  tiie  .■<npcrior  eerebelhir  peduncles;  and  behind  by  another  notch,  tiie  incisura 
cerebelli  posterior  or  incisura  marsupialis,  which  is  tlie  posterior  extrennty  of  tlic 
valley  and  lodges  the  falx  cerebelli.  The  central  lobe,  or  vermiform  process, 
presents  two  aspects:  an  npper,  seen  as  a  slight-elevation  in  the  middle  of  the 
uppi'r  surface  of  the  cerebellum,  and  called  the  superior  vermiform  jiroccss,  and  an 
inferior,  which  is  called  the  inferior  vermiform  process.  Passing  along  the  free 
border  of  each  hemisphere  is  the  great  horizontal  fissure  of  the  cerebellum,  wind) 
commences  at  the  point  where  the  middle  i)eduncle  of  the  cerebellum  enters  the 
liemisphere,  and  extends  backward  and  around  to  the  other  middle  peduncle  of  the 
cerebellum.  The  horizontal  fissure  separates  the  upper  from  the  lower  surface  of 
the  hemisphere. 

Dissection. — Before  proceeding  further  with  the  study  of  the  cerebellum, 
remove  what  remains  of  the  cerebrum  by  carrying  an  incision  through  the  optic 
thalami  and  the  crura  cerebri,  and  detach  the  pia  mater  from  the  cerebellum. 

The  Superior  Vermiform  Process  is  the  upper  surface  of  the  vermiform  pro- 
cess, or  middle  lobe  of  the  cerebellum,  and  is  raised  above  the  level  of  the  superior 
surface  of  the  hemispheres  of  the  cerebellum.  It  is  divided  into  the  following- 
lobes  :  lingula,  lobulus  centralis,  monticulus  cerebelli,  and  folium  cacuminis.  The 
lingula  overlies  the  posterior  part  of  the  superior  medullary  velum  and  is  adherent 
to  it.  It  is  attached  at  its  base  to  the  lobulus  centralis.  The  lobulus  centralis  lies 
innnediately  posterior  to  and  below  the  corpora  quadrigemina ;  it  s])reads  out 
laterally  into  the  alie  of  the  hemispheres.  The  monticulus  cerebelli  is  divided 
into  two  parts,  the  culinen  and  the  clivvs,  the  latter  being  a  sloping  part ;  it  is  con- 
nected on  each  side  to  the  quadrate  loljc.  The  culmen  joins  the  anterior  cres- 
centic  division  of  the  quadrate  lobe,  and  the  clivus  joins  the  posterior  crescentic 
division.  The  folium  cacuminis,  which  connects  the  posterior  superior  lobes  of 
the  hemispheres,  is  posterior  to  the  clivus. 

The  Tipper  Surface  of  Each  Hemisphere  of  the  Cerebellum  slopes  outward 
and  backward  from  the  superior  vermiform  process,  and  is  divided  into  two  lobes 
— the  quadrate  and  the  posterior  superior  lobe — by  the  superior  sulcus  of  the 
cerebellum,  which  passes  from  the  commencement  of  the  transverse  fissure  toward 
the  incisura  cerelielli  posterior.  The  quadrate  lobe  is  situated  anterior  to  the 
sulcus  cerebelli  superior,  and  extends  nearly  to  the  posterior  end  of  the  vermiform 
process,  its  laminse  passing  without  interruption  through  the  monticulus  cerebelli 
into  the  corresponding  lobe  of  the  opposite  side.  The  quadrate  lol)e  is  divided  by 
a  small  fissure  into  an  anterior  crescentic  and  a  posterior  crescentic  lohule.  The 
posterior  superior  lobe  is  situated  posterior  to  the  sulcus  cerebelli  superior  and 

^—       11—36 


562  SURGICAL   AXATOMY. 

along  the  posterior  border  of  the  hemisphere,  and  is  joined  to  the  posterior  superior 
lobe  of  the  opposite  side  bj'  the  folium  cacuminis. 

Dissection. — Displace  the  medulla  oblongata  forward,  and  expose  the  infe- 
rior vermiform  process  at  the  bottom  of  the  vallecula. 

The  Inferior  Vermiform  Process  is  divided  into  four  lobes,  named,  from  before 
backward,  the  nodule,  the  uvula,  the  pyramid,  and  the  tuber  valvulaj.  The 
nodule,  designated  by  Malacarne  the  laminated  tubercle,  is  tiie  anterior  extrem- 
ity of  the  inferior  vermiform  process,  and  projects  into  the  fourth  ventricle,  form- 
ing a  part  of  the  roof  of  that  ventricle.  It  is  connected  upon  both  sides  to  the 
flocculi,  upon  the  under  surface  of  the  hemispheres,  by  a  thin,  semilunar  layer  of 
white  .substance,  the  posterior  or  inferior  medullary  velum.  The  uvula,  situated 
directly  behind  the  nodule,  is  an  elongated  lobe  compressed  laterally,  and  is  con- 
nected on  each  side  to  the  amygdaloid  lobe,  or  tonsil,  by  an  indented  strip  of  gray 
matter,  the  furrowed  band.  The  pyramid,  situated  behind  the  uvula,  is  the  largest 
of  the  divisions  of  the  process,  and  connects  the  biventral  lobes  of  the  hemispheres. 
The  tuber  valvulae,  the  posterior  extremity  of  the  inferior  vermiform  proce.'is, 
connects  the  two  inferior  posterior  and  the  two  slender  lobes  of  the  hemispheres. 

The  Under  Surface  of  Each  Hemisphere  of  the  cerebellum,  which  is  convex 
and  conforms  to  the  occipital  fossa  in  which  it  rests,  is  divided  into  five  lobes, 
named,  from  before  backward,  the  flocculus,  the  amygdala,  or  ton.sil,  the  digastric 
or  biventral,  the  slender,  and  the  posterior  inferior.  The  flocculus,  the  smallest 
lobe,  is  situated  at  the  anterior  part  of  the  hemisphere,  between  the  digastric  or 
biventral  lol)e  and  the  middle  peduncle  of  the  cerebellum,  in  the  line  of  the  great 
horizontal  fissure  of  the  cerebellum.  The  amygdala,  or  tonsil,  is  .situated  to  the 
inner  side  of  the  digastric  or  biventral  lobe,  and  between  that  lobe  and  the  vallec- 
ula. It  is  connected  with  the  uvula  by  the  furrowed  band.  The  digastric  or  biven- 
tral, the  largest  lobe,  lies  behind  the  flocculus,  and  external  to  the  amygdala  and 
the  pyramid  ;  it  is  connected  with  the  digastric  lobe  of  the  other  hemisphere  by  the 
pyramid.  The  slender  lobe,  or  lobiilus  gracilis,  lies  immediately  behind  the  digas- 
tric liilie,  and  external  to  the  jiyramid  and  the  tuber  valvuhe.  The  posterior  infe- 
rior lobe  lies  between  tlie  posterior  border  of  the  hemisphere  and  the  slender  lobe, 
and  extei'nal  to  the  tuber  valvulte. 

Dissection. — Cut  away  the  amygdala  on  one  side,  or  slice  off  the  digastric 
and  slender  loltes  until  the  amygdala  can  l)e  turned  out;  this  will  expose  the  fur- 
rowed hand,  tJie  posterior  mrdullaiy  velum  and  the  fossa,  known  as  the  ".swal- 
low's nest "  (/(•/(/(«  liirinidijiis).  wh'wh  is  iniU'Uted  l)y  the  posterior  nK'dullary  velum, 
the  nodule,  and  the  uvula. 

The  Peduncles  of  the  Cerebellum  arc  the  supei'ior,  the  middle,  and  the 
inferini'. 


PLATE  CXXXIX. 


Head  of  caudate  nucleus 
Lenticular  nude 


Anterior  cornu  of  riglit  lateral  ventricle 


Claustrum 


Genu  of  corpus  callosum 


CORONAL  SECTION  OF  CEREBRUM. 
5G4 


PLATE  CXI, 


Island  of  Rcil 


Corpus  callosum 
Choroid  plexus 


Fifth  ventricle 

m  lucidum 
Caudato  nucleus 


Te 


Optic  n 
Lamina  cinerea' 
Optic  commissure 


Internal  capsule 
Anterior  commissure 
Pons  Varolii 
Pituitary  body 


CORONAL  SECTION  OF  CEREBRUM  JUST  ANTERIOR  TO  OPTIC  CHIASM, 

5G5 


\ 


SECTIOXS  OF   THE  BRAIN.  r>(]7 

The  superior  peduncles  of  the  cxTcbeUuni  cuinu'ct  the  cerebt'lhini  witli  tin; 
cerehruni,  and  j)ass  forward,  forming  the  Uiteral  boundaries  of  tlie  anterior  portion 
of  the  fourtli  ventricle.  Under  the  floor  of  the  aqueduct  of  Sylvius  the  two 
superior  i)eduncles  decussate  ;  each  peduncle  then  enters  the  opposite  subthalamic 
region  of  the  cerebrum,  to  reach  the  uptit'  tiialamus  and  lenticular  nucleus.  The 
middle  pcdunck's  counect  tliL'  cerebellum  with  the  pons.  The  inferior  peduncles  ave 
formed  'by  the  restiform  bodies,  and  connect  the  cerebellum  with  the  medulla 
oblongata  and  spinal  cord. 

Dissection. — Carry  a  vertical  incisiun  through  the  center  of  the  hemisphere 
of  the  cerebellum,  to  expose  the  white  matter  and  gray  nucleus. 

Interior  Arrangement. — In  the  interior  of  the  white  matter  of  the  cere- 
helhun  is  a  gray  nucleus,  the  corpus  dentatum.  The  white  matter  sends  processes 
into  the  lamiuce  of  the  gray  matter,  which  forms  the  surface  of  the  cerebellum, 
and  give  rise  to  the  appearance  that  has  been  termed  the  arbor  viUe.  The  corpus 
dentatum  of  the  cerebellum,  like  the  nucleus  of  the  same  name  in  the  olivary 
bod_v,  is  arranged  in  the  form  of  a  capsule  presenting  a  zigzag  outline  which  is 
open  at  the  inner  side.  Through  this  open  part,  or  hilum,  of  the  capsule  a  bundle 
of  white  fibers  passes  to  the  sujierior  peduncles  of  the  cerebellum  and  the  A'alve 
of  Vieusseus. 

SECTIONS    OF   THE    BRAIN. 

Having  mastered  the  topography  of  the  enccjihalon,  together  with  its  intra- 
ventricular aspect,  in  the  study  of  whi(/li  some  of  its  parts  were  seen  in  horizontal 
sections,  it  will  now  be  well  to  study  coronal  and  sagittal  sections,  and  so  obtain 
a  more  accurate  knowledge  of  the  relations  of  tlie  various  parts  of  the  enceph- 
alon. 

A  sagittal  section  lies  in  a  vertical  longitudinal  plane,  running  antei'o-poste- 
riorly,  as  if  through  the  entire  length  of  the  brain  through  or  parallel  with  the 
sagittal  suture,  hence  it  is  so  named  ;  a  section  of  this  kind  is  not,  however, 
limited  to  the  median  line. 

A  coronal  section  lies  in  a  vertical  transverse  plane,  running  from  side  to  side, 
at  right  angles  to  a  sagittal  plane  ;  this  is  also  called  a  frontal  section. 

A  coronal  section  through  the  brain  at  the  tips  of  the  temporo-sjjhenoid  lobes 
will  traverse  the  anterior  end  of  the  lenticular  nucleus  of  the  corpus  striatum,  and 
one  a  short  distance  beyond  this  will  pass  through  the  anterior  end  of  the  caudate 
nucleus.  A  section  passing  through  the  optic  commissure,  or  just  behind  it,  will 
include  the  front  of  the  optic  thalami.  A  frontal  section  must,  therefore,  be  made 
back  of  the  optic  commissure  if  it  is  to  include  both  .sets  of  basal  ganglia. 

A  coronal  section  about  midway  between  the  optic  commissure  and  the  tijjs  of 


568  SURGICAL  ANATOMY. 

the  temporo-sphenoid  lobes  will  not  include  the  optic  thalami.  It  will  expose, 
from  within  outward,  the  septum  lucidum,  the  lateral  ventricle  with  the  corpus 
callosum  above  it,  the  caudate  nucleus,  the  internal  capsule,  the  lenticular  nucleus, 
the  external  capsule,  the  claustrum,  the  white  matter,  the  island  of  Reil,  and  the 
fissure  of  Sylvius.  The  wedge  shape  of  the  lateral  ventricle  is  |ilainly  shown  in 
this  section,  as  is  also  the  formation  of  its  outer  wall  and  part  of  its  floor  Vjy  the 
sloping  caudate  nucleus.  The  lenticular  nucleus  is  clearly  separated  into  three 
portions,  defined  by  fine  white  curved  lines  extending  between  them. 

AVhen  these  sections  are  made  further  back,  the  anteriorly  situated  j^arts 
become  smaller,  and  finally  disappear,  while  the  more  posteriorly  situated  parts 
gradually  increase  in  size  ;  the  caudate  nucleus  grows  smaller  and  recedes  toward  the 
upper  and  outer  angle  of  the  lateral  ventricle,  while  the  optic  thalamus  occupies 
an  increasing  amount  of  the  lower  part  of  the  outer  wall  of  the  lateral  ventricle. 
Notable  changes  in  the  median  line  also  occur,  the  fifth  ventricle  and  the  septum 
lucidum  vanish,  and  the  fornix  and  third  ventricle  appear  instead,  while  the  infun- 
dibulum,  mammillary  bodies,  and  posterior  perforated  spaces  successively  appear  at 
the  base.  The  crura  cerebri  at  first  appear  to  be  separated,  gradually  coming 
closer,  until  they  merge.  The  locus  niger  is  distinctly  visible,  as  are  also  the  two 
adjacent  divisions  of  the  crura  cerebri.  The  upper  or  front  end  of  the  pons  comes 
into  view,  and  at  its  upper  edge  the  aqueduct  of  Sylvius  appears.  The  velum 
interpositum,  containing  the  choroid  plexuses,  becomes  wider  as  the  sections  pass 
backward.  The  ta^nife  semicirculares,  the  dentate  fascite,  the  hipp<X'ampal  gyri, 
and  the  middle  cornua  of  the  lateral  ventricles  are  also  seen  in  these  sections. 

No  study  of  the  cerebrum  is  complete  without  a  careful  consideration  of  these 
sections,  as  they  portray  exactly  the  relations  of  the  cortex  and  intra-encephalic 
parts  to  one  another. 

Sagittal  sections  do  not  offer  so  wide  a  field  for  the  study  of  these  relations, 
because  of  the  rapid  loss  of  important  structures  as  the  median  line  is  departed 
from,  though  the  length  of  the  liasal  ganglia,  and  particularly  of  the  caudate 
nucleus,  is  better  shown  in  these  sections  than  in  other  ways. 


PLATE  CXLl. 


Fornix^ 
Choroid  plexu 
Body  of  lateral  ventric 
Optic  thalamu 
Caudate  nucleus, 


iVelum  interpositum 
Ccrpus  callosum 


Internal  capsule 
Fissure  of 


Hippocampal  fissure 

Third  ventricle 
Corpora  albicantia 


Optic  tract 
Middle  commissure 


CORONAL  SECTION  OF  CEREBRUM  THROUGH  CORPORA  ALBICANTIA  AND  MIDDLE  COMMISSURE. 

5G9 


/ 


PLATE  CXLII. 


LINES  IN  WHICH  BONE  IS  DIVIDED  IN  EXCISION  OF  UPPER  JAW. 


572 


JOIXTS    OF   THE  HEAD   AXD   yECK.  573 

JOiyrs    OF    THE    HEAD   AXD   NECK. 

Tlu"  Joints  of  the  Skull,  rxcciitiu;;'  tlio  temi)oro-inaxillai-y  articulation  and 
the  artioulatiouri  between  tlie  skull  anil  llic  spinal  coluuni,  are  in  (lie  form  of 
sutures  wliieh  atlbnl  imnioliility  ami  liniiiirss  with  elasticity. 

The  Sutures  of  the  Skull  may  be  mistaken  for  fractures,  ami  the  \\'ormian 
bones,  which  are  situated  iu  the  lines  of  the  sutures,  may  be  mistaken  for  frag- 
ments outlined  by  fractures. 

The  sagittal  suture  is  situated  in  the  median  line  of  tlie  vault  of  the 
la-anium,  ami  extends  from  the  l>regma  to  the  lambila.  The  bregma  is  situated  at 
the  junction  of  the  coronal  and  sagittal  sutures,  and  at  the  ])oint  ■where  a  line, 
drawn  perpendicular  to  Reid's  base  line  at  the  j^reauricular  fossa,  crosses  the 
median  line  of  the  cranial  vault.  The  lambda  is  situated  at  the  junction  of  the 
sagittal  and  lambdoid  sutures,  and  about  two  and  three-fourth  iuchc.Sj  or  seven 
centimeters,  above  the  external  occii>ital  jirotuljcrance. 

The  coronal  suture  extends  from  the  bregma  downward,  and  slightly 
forward,  towai'd  the  juni'tion  of  the  zygoma  with  the  malar  bone. 

The  lambdoid  suture  is  situated  at  about  the  upper  two-thirds  of  a  line 
drawn  from  the  lambda  to  the  apex  of  the  mastoid  process  of  the  temporal  l)one. 
Ailditional  sutures  not  conniionly  present  may  exist  in  the  vault  of  the  cranium 
and  be  mistaken  for  fractures.  These  are  the  frontal  suture,  which  extends 
forward  between  the  halves  of  the  frontal  bone  in  the  line  of  the  sagittal  .suture, 
the  parietal  fissure,  a  short  suture  which  crosses  the  sagittal  suture  one  inch, 
or  two  and  one-half  centimeters,  anterior  to  the  lambda,  and  the  transverse 
occipital  fissure,  which  is  a  suture  situated  in  the  occipital  bone  near  the  level 
of  the  external  occipital  protuberance. 

The  Temporo-maxillary  Articulation  is  the  joint  situated  between  the  con- 
dyle of  the  inferior  maxilla  below,  and  the  anterior  part  of  the  glenoid  fossa  and 
the  eminentia  articularis  above.  It  is  a  ginglymo-arthrodial  articulation,  or  hinge 
joint,  modified  to  allow  gliding  movement.  The  ligaments  of  the  temporo- 
maxillary  articulation  are  the  capsular  ligament  and  the  intorarticvilar  tibro- 
cartilage.  The  joint  is  strengthened  by  the  spheno-mandibular  and  stylo-man- 
dibular  ligaments. 

The  capsular  ligament  is  thin,  especially  at  its  anterior  and  inner  portions. 
It  is  attached  above  to  the  margins  of  the  articular  surface  formed  by  the 
eminentia  articularis  and  anterior  portion  of  the  glenoid  cavity  of  the  temporal 
bone,  and  below  to  the  neck  of  the  lower  jaw.  Its  external  ]iortion  is  much 
stronger  than  the  remainder  of  the  cap.sule,  and  is  termed  the  external  lateral  liga- 
ment. 


574  SURGICAL  ANATOMY. 

The  external  lateral  ligament  is  attached  above  to  the  lower  margin  of  the 
zygoma  ami  the  tuljercle  of  tlie  zygoma,  its  fibers  jjassiiig  downward  and  back- 
ward to  be  attached  below  to  the  outer  surface  and  posterior  margin  of  the  neck  of 
the  lower  jaw. 

The  interarticular  fibro-cartilage  is  situated  between  the  articular  surfaces  of 
the  bones  entering  into  the  formation  of  the  joint.  Through  conformation  to  these 
surfaces  its  upper  surface  is  concavo-convex  from  before  backward  and  convex 
laterally',  and  the  posterior  portion  of  its  under  surface  is  concave,  to  fit  the  con- 
dyle. It  is  thinner  at  its  center,  and  thickest  posteriori}^,  where  it  acts  as  a  buffer 
and  protects  the  thin  bone  of  the  glenoid  fossa.  Its  margins  are  attached  to  the 
capsular  ligament,  and  some  of  the  fibers  of  the  tendon  of  the  external  pterygoid 
muscle  pass  between  the  fibers  of  the  anterior  portion  of  the  capsular  ligament,  to 
be  inserted  into  the  anterior  margin  of  the  interarticular  fibro-cartilage. 

The  synovial  membranes  are  two  in  number,  the  superior  synovial  mem- 
brane being  separated  from  the  inferior  by  the  interarticular  fibro-cartilage. 
When  the  interarticular  fibro-cartilage  is  perforated,  the  two  synovial  sacs  com- 
municate. 

The  spheno-mandibular  or  internal  lateral  ligament  is  attached  above  to  the 
spine  of  the  greater  wing  of  the  sphenoid  bone  and  adjacent  part  of  the  temporal 
bone,  and  below  to  the  spine  of  Spix,  or  mandibular  spine,  which  is  situated  on 
the  inner  surface  of  the  lower  jaw,  below  and  internal  to  the  inferior  dental  for- 
amen. The  internal  lateral  ligament  is  separated  from  the  temporo-maxillary  joint 
and  lower  jaw  by  the  internal  maxillary  artery  and  vein,  the  middle  meningeal 
artery,  the  external  pterygoid  muscle,  the  inferior  dental  vessels  and  the  inferior 
dental  nerve.     Its  lower  extremity  is  pierced  by  the  mylo-hyoid  nerve. 

The  stylo-mandibular  or  stylo-maxillary  ligament  is  a  jjart  of  that  process 
of  the  deep  cervical  fascia  wliich  dips  beneath  the  parotid  gland.  It  extends  from 
the  stj'loid  process  of  the  temporal  bone  to  the  angle  and  postei'ior  margin  of  the 
ramus  of  the  lower  jaw,  separating  the  parotid  from  the  submaxillary  gland. 

Blood  Supply. — From  the  temporal,  middle  meningeal,  and  ascending 
pharyngeal  arteries. 

Nerve  Supply. — From  the  auriculo-temporal  and  masseteric  branches  of  the 
inferior  maxillary  nerve. 

.Movements. — Rotation  of  the  condyle  around  a  transverse  axis  occurs  when 
the  inDutli  is  opened  or  closed,  and  gliding  forward  of  both  the  condyle  and  the 
interarticular  cartilage  A\hcn  the  mouth  is  widely  opened.  If  the  mouth  is  opened 
too  wid(  ly,  as  in  a  convulsive  yawn,  the  condyle  and  interartii'ular  fibro-cartilage 
may  be  completely  or  incompletely  dislocated  forward,  and  locked  either  in  front  of 
or  uiion  the  eminentia  articularis.     In  closing  the  mouth  the  cartilage  and  condvle 


PLATE  GXllll. 


External  lateral  lig 


Capsular  lig.       '  '' 


Styloid  process 


Stylo-maxillary  lig. 


Stylo-hyoid  lig. 


TEMPORO-MAXILLARY  ARTICULATION-EXTERNAL  VIEW. 
576 


PLATE  CXLIV, 


Capsular  lig 
Styloid  process 


nternal  lateral  liar 


Stylo-hyoid  lig 


Stylo-maxillary  lis 


f!_  II-. ■',7 


TEMPORO-MAXILLARY  ARTICULATION-INTERNAL  VIEW. 


0(  / 


JOIXTS   OF  THE  HEAD  AM)  NECK.  579 

glide  backward,  and  the  condj-le  rotates  on  the  cartilage  in  the  reverse  direction. 
These  movements  result  in  a  combination  of  a  hinge  movement  of  the  condyle 
with  fore-and-aft  gliding  movement  of  the  interarticular  iibro-carlilagc  (iliding 
movement  of  the  interarticular  fibro-cartilage  forward  occurs  when  the  lower 
jaw  and  chin  are  thrust  forward.  Kutation  of  the  condyle  around  tlic  vertical 
axis  of  the  neck  of  the  lower  jaw,  associated  with  oblique  gliding  of  the  inter- 
articular fibro-cartilage  on  the  glenoid  fossa,  occurs  in  tlic  oljlicjuc  movements 
of  tlie  lower  jaw  in  mastication. 

The  Joints  of  the  Neck  are  those  of  the  cervical  portion  of  the  spinal  column, 
which  have  been  described  in  volume  i. 

Dislocations. — Dislocation  of  the  bones  of  the  vault  and  base  of  the  skull 
is  almost  entirely  limited  to  the  young  skull.  Such  an  accident  rarely  occurs  in 
the  adult  skull,  the  firm  union  and  overlapping  of  the  bones  preventing  disloca- 
tion of  these  articulations.  The  scjuamous  suture  has  been  separated  by  dis- 
location of  the  temporal  bone.  Fractures  in  the  line  of  the  coronal,  sagittal,  and 
lambdoid  sutures  have  occurred. 

Dislocation  of  the  lower  jaw  is  of  comparatively  rare  occurrence,  and 
is  usually  forward  and  bilateral.  Forivard  dislocation  occurs  M'hile  the  mouth  is 
wide  open,  as  during  convulsive  yawning,  manipulations  of  dentists,  or  from 
blows  on  the  chin.  Only  a  small  amount  of  force  is  required  at  such  a  time  to 
carry  the  condyle  from  a  position  just  behind,  to  a  point  upon  or  immediately 
in  front  of,  the  summit  of  tlie  eminentia  articularis.  The  anterior  portion  of  the 
capsular  ligament  is  torn  ;  the  interarticular  fibro-cartilage  is  usually  dislocated 
with  the  condyle.  The  condyle  is  retained  in  its  abnormal  position  by  the 
upward  traction  of  the  temporal,  masseter,  and  internal  pterygoid  muscles. 
Backward  dislocation  of  the  lower  jaw  may  follow  a  blow  on  the  chin,  and  the 
condyle  may  fracture  the  bony  portion  of  the  external  auditory  meatus  or  be 
driven  into  the  cranial  cavity. 

Excisions. — Excision  of  the  upper  jaw  is  usually  performed  for  malignant 
disease,  as  sarcoma  or  carcinoma  of  the  maxillary  sinus  or  antrum  of  High- 
more.  Generally  but  one  superior  maxilla  is  removed,  although  both  upper  jaws 
have  been  removed  in  one  operation. 

In  excising  the  superior  maxilla  several  anatomic  facts  are  to  be  remembered. 
The  upper  jaw  is  in  reality  a  shell  of  bone  which  envelops  the  maxillary  sinus, 
forms  a  large  part  of  the  floor  of  the  orbit,  roof  of  the  mouth,  external  wall  of 
the  nasal  fossa,  anterior  wall  of  the  spheno-maxillary  fossa  and  pterygo-maxillary 
region,  and  bony  basis  of  the  front  of  the  face  below  the  infra-orbital  ridge.  Its 
strongest  portions  are  the  malar,  alveolar,  and  palatal  processes. 

In  the  operation  of  excision  of  the  superior  maxillary  bone  the  inferior  tur- 


580  SURGICAL  ANATOMY. 

biuated  bone,  jmrt  of  the  malar  bone,  part  of  the  palate  bone,  and  the  superior 
maxillary  bone,  except  the  ujDper  part  of  its  nasal  process,  are  removed. 

In  the  method  of  excision  which  is  most  commonly  practised, — that  is,  by  a 
median  incision, — the  first  incision  is  begun  one-half  of  an  inch,  or  slightly  less  than 
one  and  one-half  centimeters,  below  the  inner  canthus  of  the  eyelids.  It  is  carried 
downward  along  the  groove  between  the  nose  and  face,  around  the  ala  of  the  nose, 
below  the  base  of  the  nose  to  the  median  line,  and  thence  through  the  median  line 
of  the  upper  lip.  This  incision  divides  skin,  superficial  fascia,  some  of  the  muscles 
of  expression,  the  angular  artery  and  vein,  the  lateral  nasal  arterj',  the  arteiy  of 
the  nasal  septum,  the  superior  coronary  artery,  and  branches  of  the  infra-orbital 
and  facial  nerves. 

The  second  incision  is  carried  from  the  point  at  which  the  first  incision  was 
commenced  outward  along  the  infra-orbital  margin  to  a  point  over  the  malar  bone. 
This  incision  divides  a  few  insignificant  blood-vessels.  The  tissues  of  the  flap  out- 
lined are  now  quickly  reflected  outward,  removing  all  of  them  down  to  the  bone, 
not  considering  the  periosteum.  In  elevation  of  this  flap  the  infra-orbital  vessels 
and  nerve  are  divided. 

The  fibro-cartilaginous  lateral  portion  of  the  nose  is  detached  from  the  supe- 
rior maxilla,  and  the  base  of  the  nasal  process  of  the  superior  maxilla  is  severed 
with  a  fine  saw  or  a  chisel.  The  periosteum  is  divided  along  the  infra-orbital 
ridge,  and  elevated  from  the  floor  of  the  orbit,  at  the  same  time  detaching  the 
origin  of  the  inferior  oblique  muscle  of  the  eyeball.  The  inner  part  of  the  floor  of 
the  orbit  is  then  divided  with  a  small  chisel.  The  malar  bone  is  next  severed  at 
its  middle  with  a  small  saw  or  chisel,  and  in  a  line  which  extends  obliquely  down- 
ward and  outward.  The  saw  is  carried  through  the  floor  of  the  orbit  until  it 
reaches  the  spheno-maxillary  fissure.  The  malar  bone  can  be  divided  with  strong 
bone  forceps,  which  are  not  allowed  to  extend  into  the  spheno-maxillary  fissure. 
If  the  forceps  are  inserted  too  deeply  into  the  fissure,  the  internal  maxillary  artery 
may  be  severed. 

The  central  incisor  on  the  diseased  side  is  extracted,  the  muco-periosteum  of 
the  floor  of  the  nose  is  divided  close  to  the  nasal  septum,  the  muco-periosteum  of 
the  hard  palate  is  severed  in  the  median  line,  and  the  soft  palate  is  thoroughly 
separated  from  the  hard  palate.  "With  a  slender  saw  introduced  through  the  nose 
the  hard  palate  is  divided  close  to  the  nasal  septum. 

With  one  blade  of  the  forceps  at  the  infra-orbital  ridge  and  the  other  at  the 
alveolar  process,  the  jaw  is  grasped  with  lion  forceps,  and  loosened  from  the  remain- 
ing attachments.  This  procedure  fractures  the  vertical  plate  of  the  palate  bone, 
and  detaches  the  jaw  from  the  pterygoid  process  of  the  sphenoid  bone. 

The   vessels   ruptured   or   divided   in   removing   the    superior    maxilla   are 


PLATE  CXLV, 


Externaf  pterygoid  m-^ 


atysma,  digastric,  mylo-hyoid, 
enio-hyoid,  and  gento-hyo-glossus  muscles 

DOUBLE  FRACTURE  OF  LOWER  JAW  AT  MENTAL  FOR.AMINA. 


FRACTURES  OF  LOWER  JAW, 
581 


JOINTS   OF   THE  JIEAD  AND   NECK.  583 

braiii-lies  of  tlie  tliird  portion  of  tlie  internal  maxillary  artery.  They  are  the 
alveolar,  iniVa-orbital,  posterior  palatine,  pterygo-palatine,  and  naso-palatine  arteries, 
or  some  of  their  branches.  The  application  of  the  actual  cautery  may  be  required 
to  check  hemorrhage.  The  cavity  may  be  packed  with  gauze,  and  the  wound  in 
the  skin  is  closed.     The  gauze  is  subsef[uently  removed  through  the  mouth. 

Excision  of  the  lower  jaw  is  i)eri'ormed  for  the  removal  of  malignant  growths 
of  that  bone.  Usually  but  half  of  the  bone  is  excised.  Segments  of  the  lower  jaw 
are  removed  in  extirpation  of  benign  tumors  of  that  bone.  The  incision  is  carried 
from  the  attached  margin  of  the  lower  lij)  down  the  middle  of  the  chin  to  the  lower 
margin  of  the  jaw,  thence  just  below  and  parallel  with  the  body  of  the  jaw  to  the 
angle,  and  thence  upward  along  the  posterior  margin  of  the  ramus  of  the  lower  jaw 
to  the  level  of  the  lobule  of  the  ear.  In  making  this  incision  the  facial  artery 
is  secured  between  ligatures  before  it  is  divided.  The  skin,  superticial  fascia, 
platysma  myoides  muscle,  and  deep  fascia  are  divided  ;  the  parotid,  submaxillary, 
and  sublingual  glands  and  Stenson's  duct  must  be  avoided. 

Beginning  at  the  symphysis,  the  soft  tissues  are  detached  from  the  external 
surface  of  the  bone  with  a  periosteal  elevator.  The  depressor  labii  inferioris, 
depressor  anguli  oris,  buccinator,  and  masseter  muscles  are  thus  separated  from  the 
bone. 

After  extraction  of  one  of  the  incisor  teeth  the  bone  is  divided  with  a  small 
saw.  The  divided  end  of  the  bone  is  next  drawn  outward,  and  the  mylo-hyoid 
muscle  and  mucous  membrane  of  the  mouth  are  divided  close  to  the  bone,  being 
careful  to  avoid  injuring  the  sublingual  or  submaxillary  gland  or  the  lingual 
nerve. 

The  internal  pterygoid  muscle  is  detached  from  the  bone  with  a  periosteal 
elevator,  and  the  internal  lateral  ligament  of  the  lower  jaw  and  inferior  dental 
vessels  and  nerve  are  divided. 

The  jaw  is  now  depressed,  to  bring  the  coronoid  process  into  view.  This  pro- 
cess is  then  divided  with  a  chisel  and  a  mallet,  and  dissected  out  afterward,  or  the 
tendon  of  the  temporal  muscle  is  severed  with  curved  scissors.  The  tendon  of  the 
external  pterygoid  muscle  is  divided  with  scissors,  or  detached  with  a  periosteal 
elevator. 

The  capsular  ligament  is  divided,  and,  after  severing  some  few  remaining 
attachments,  as  the  stylo-maxillary  ligament,  the  bone  can  be  removed.  After 
bleeding  has  been  checked  the  wound  is  closed. 

The  structures  to  be  avoided  in  this  operation  are  the  three  salivary  glands, 
Stenson's  duct,  the  buccal  and  supra-maxillary  branches  of  the  facial  nerve,  the 
lingual  and  auriculo-temporal  nerves,  the  external  carotid,  temporal,  and  internal 
maxillary  arteries,  and  the  temporo-maxillary  and  internal  maxillary  veins.     The 


584  SURGICAL  ANATOMY. 

vessels  which  must  be  divided  are  the  facial,  inferior  labial,  mental,  mylo-hyoid, 
inferior  dental,  and  masseteric  arteries  and  veins. 

Excision  of  the  condyle  of  tJie  lower  jaw  is  performed  most  commonly  for 
disease  of  the  temporo-maxillary  articulation  causing  impaired  movement  in 
that  jaw. 

A  vertical  incision  is  carried  from  the  zygoma  downward  over  the  condyle  of 
the  lower  jaw,  to  a  point  just  above  the  position  of  the  transverse  facial  artery, 
which  is  one  centimeter,  or  less  than  one-half  of  an  inch,  below  and  parallel  with 
the  zygoma.  A  second  incision  is  carried  forward  along  the  lower  margin  of  the 
zygoma  for  one  inch,  or  2.5  centimeters.  The  flap  thus  outlined  is  reflected  for- 
ward and  downward,  avoiding  the  temporal  branches  of  the  facial  nerve.  The 
posterior  fibers  of  the  masseter  muscle  are  detached  from  the  zj'goma,  and  the 
capsule  of  the  temporo-maxillary  joint  is  opened. 

The  neck  of  the  condyle  is  divided  with  a  chisel  or  a  small  saw,  the  condyle 
being  firmlj'  held  with  a  small  hook.  The  condyle  is  twisted  out  of  the  glenoid 
fossa,  and  the  external  pterj^goid  tendon  and  capsular  ligament  are  divided.  The 
instruments  are  kept  close  to  the  bone,  to  avoid  injuring  the  temporal,  internal 
maxillary,  and  masseteric  vessels,  the  auriculo-temporal  and  masseteric  nerves,  and 
the  parotid  gland. 

Development  of  the  Bones  of  the  Skull. — The  bones  of  the  vault  of  the 
cranium  are  developed  in  membrane,  and  those  of  the  base  of  the  skull  are  formed 
in  cartilage.  Just  before  birth  the  bones  of  the  vault  are  imperfectly  ossified  at 
their  margins,  so  that  they  are  joined  by  membrane  instead  of  by  sutures.  This 
condition  of  the  bones  allows  diminution  in  the  diameters  of  the  fetal  skull  at 
birth  by  overlapping  of  the  bones  of  the  cranial  vault. 

At  birth  the  bones  are  incompletely  ossified  at  the  angles  of  the  parietal 
bone  ;  these  meml)ranous  areas  are  called  fontanels. 

The  posterior  fontanel  is  triangular  in  shape,  is  situated  at  the  lambda,  and 
closes  during  the  first  few  months  after  birth. 

The  anterior  fontanel  is  quadrilateral,  is  located  at  the  bregma,  and  closes 
during  the  latter  half  of  tlie  second  year. 

Tlie  antero-lateral  fontanels,  situated  at  the  anterior  inferior  angles  of  the 
l^rietal  bones,  and  tlie  postero-lateral  fontanels,  situated  at  the  posterior  inferior 
angles  of  the  parietal  bones,  close  .soon  after  birth.  Imperfect  or  delayed  ossifica- 
tion at  the  fontanels  occurs  in  hydrocephalus. 

Fractures  of  the  Skull. — Tlie  bones  of  the  skull  in  young  children  are  not 
readily  iVacturcd.  AVlicn  force  is  applied  to  tlie  vault  of  the  skull  of  a  young 
infant,  it  is  merely  indented,  ossification  l)eing  so  incomplete  that  the  bones  are 
flcxihlc. 


FRACTURES  OF  THE  HEAD  AXD   NECK.  585 

The  adult  skull  is  not  readily  liactuivd,  because  its  curves  diffuse  and 
diminish  the  breaking  iorce,  and,  being  composed  of  three  tables  of  dilferent 
consistence,  its  strength  and  elasticity  are  much  enhanced.  Other  cduditions 
which  lessen  the  danger  of  fracture  of  the  vault  of  the  cranium  are :  The 
mobility  of  the  scalp  proper,  the  rounded  shape  of  the  cranial  vault,  and  the 
mobility  of  the  head.  As  age  advances  and  the  bones  become  less  porou.s,  less 
elastic,  and,  at  the  fortieth  year,  the  sutures  begin  to  be  obliterated  by  ossification 
of  the  inter.'^utural  membrane  the  skull  is  more  readily  fractured.  JOillirr  the 
external  table  or  the  internal  table  may  l)e  IVaetured  without  injury  to  the  other 
table,  but  both  tables  are  usually  traversed  by  the  fracture.  On  account  of  its 
brittleness  and  the  diffusion  of  the  foi'ce  in  pas.sing  through  the  bone,  the  inner 
table  is  much  more  splintered  than  the  external.  In  depressed  fractures  of  the 
vault  the  inner  table  may  not  be  broken,  the  outer  table  being  merely  driven 
into  the  diploe  or  one  of  the  frontal  sinus 

Fractures  of  the  vault  of  the  skull  are  due  to  direct  violence.  A  fracture  of 
the  vault  resulting  from  dilluse  application  of  force,  as  in  a  fall  upon  the  head, 
usually  extends  to  the  base  of  the  skull  by  the  shortest  route,  regardless  of  sutures 
or  thickness  of  the  bones  traversed.  This  is  more  likely  to  occur  if  the  fracture  be 
linear.  Fractures  of  the  frontal  region  extend  into  the  floor  of  the  anterior  cranial 
fossa,  those  of  the  parietal  region  into  the  floor  of  the  middle  cranial  fossa,  and 
those  of  the  occipital  region  into  the  floor  of  the  posterior  craliial  fos.sa. 

Fractures  of  the  base  of  the  skull  are  caused  by  extension  of  a  fracture  fi-om 
the  vault  of  the  skull  and  by  direct  or  indirect  A'iolence.  Fractures  of  the  base 
by  direct  violence  have  been  caused  b}'  foreign  bodies  having  been  driven  through 
the  roof  of  the  orbit,  nose,  or  pharynx.  Fractures  of  the  base  by  indirect  violence 
usually  result  from  the  body  falling  ujion  the  feet,  knees,  or  buttocks,  and  fnim 
the  upper  part  of  the  spinal  column  being  driven  against  or  through  the  occipital 
bone.  In  blows  at  the  root  of  the  nose  the  cribriform  plate  of  the  ethmoid  bone 
may  be  fractured,  and  in  a  fall  upon  the  chin  the  condyle  of  the  lower  jaw  may  be 
driven  through  the  base  of  the  skull  at  the  middle  cranial  fossa.  The  cribritbrm 
plate  of  the  ethmoid  bone  has  been  In'oken  by  counter-stroke  by  a  Ijlow  in  the 
occipital  region. 

In  fracture  of  the  base  of  the  skull  at  the  anterior  cranial  fossa  blood  may 
enter  the  orbit  and  produce  a  subconjunctival  ecchymosis,  or  blood  and  cerebro- 
spinal fluid  may  escaj^e  from  the  nose  through  the  anterior  nares  or  posterior  nares 
and  mouth.  The  blood  escaping  into  the  orbit  is  derived  from  ruptured  menin- 
geal vessels,  anterior  or  posterior  ethmoid  vessels,  and  ophtbalmir  arteiy  or  vt'in  ; 
that  entering  the  nose  escapes  from  the  anterior  or  jiosterior  ethmoid  vessels,  and 
the  vessels  of  the  nasal  mucous  memlirane.     In  fracture  of  the  cribritbrm  plate  of 


586  SURGICAL  AXATOMY. 

the  ethmoid  bone  rupture  of  the  olfactory  nerves  niaj'  cause  loss  of  the  sense  of 
smell.  In  fractures  at  the  middle  cranial  fossa  blood  and  cerebro-spinal  fluid  may 
escape  from  the  ear.  To  permit  cerebro-spinal  fluid  to  escape  in  this  manner,  the 
arachnoid,  dura  mater,  bone  and  mucous  membrane  of  the  wall  of  the  tym- 
panum, and  membrana  tympani  must  be  ruptured.  In  fracture  of  the  base  at 
this  fossa  the  cavernous  sinus  may  be  ruptured,  and  if  the  fracture  extend  across 
the  petrous  portion  of  the  temporal  bone,  the  superior  petrosal  sinus,  and  the 
facial  and  auditory  nerves  may  be  injured.  Laceration  of  the  facial  nerve  causes 
paralysis  of  the  muscles  of  expi'ession  and  of  the  buccinator  muscle ;  laceration 
of  the  auditory  nerve  causes  deafness.  In  fractures  of  the  base  of  the  skull  at 
the  posterior  cranial  fossa  blood  may  be  extra vasated  into  the  tissues  of  the  najse  or 
posterior  triangle  of  the  neck.  The  symptoms  of  fracture  of  the  skull  are  chiefly 
those  of  compression  of  the  brain,  produced  b}'  extravasated  blood  which  arises 
from  rupture  of  the  meningeal  vessels,  sinuses  of  the  dura  mater,  and  diploic 
veins. 

Fractures  of  the  Bones  of  the  Face  are  the  result  of  direct  violence.  In 
fracture  of  the  nasal  bones  emphysema  of  the  soft  tissues  may  occur.  In  fracture 
of  the  lacrymal  bone  obstruction  of  the  nasal  duct  may  cause  the  tears  to  flow  over 
the  cheek,  and  laceration  of  the  muco-periosteal  wall  of  the  duct  may  induce 
emphysema  of  the  soft  tissues.  In  comminuted  fracture  of  the  zygomatic  arch 
fragments  of  bone  driven  into  the  temporal  muscle  may  interfere  with  the  move- 
ments of  the  lower  jaw  in  mastication. 

Fracture  of  the  bone  of  the  upper  jaw  may  cause  profuse  hemorrhage  from 
a  ruptured  infra-orbital,  superior  dental,  anterior  palatine,  or  posterior  palatine 
artery. 

Fracture  of  the  lower  jaw  occurs  more  frecjuently  than  fracture  of  any  other 
bone  of  the  face.  It  is  usuall)'  broken  b}'  direct  violence.  In  fractures  of  the  neck 
of  the  lower  jaw  the  condyle  is  drawn  forward  by  the  external  pterygoid  muscle. 
Imperfect  apposition  and  persistent  mobility  of  the  fragments  may  induce  excessive 
formation  of  callus,  which  may  subsec|uently  cause  more  or  less  ankylosis  of  the 
temporo-maxillary  articulation.  In  fracture  of  the  ramus  of  the  bone  there  is 
slight  displacement  of  the  fragments,  as  the  massetcr  and  internal  pterygoid  muscles 
act  as  splints.  In  fracture  in  front  of  tlie  attachment  of  the  masseter  muscle 
the  posterior  fragment  is  drawn  upward  by  the  masseter,  temporal,  and  internal 
pterygoid  muscles  ;  if  the  plane  of  fracture  extends  obliquelj'  backward  and  outward, 
the  posterior  fragment  is  also  drawn  inward  by  the  internal  pterygoid  muscle.  The 
anterior  fragment  is  carried  downward  by  the  fracturing  force,  the  platysma 
myoides,  digastric,  mylo-hyoid,  genio-hyoid,  and  genio-hyo-glossus  muscles.  In 
donlilc  fracture  at  the  mental  foraniiun  the  middle  fragment  is  carried  downward 


SURFACE  AXATOMY  OF  THE  CRANK 'M.  587 

and  l)ack\vanl  by  its  wiM^lit,  ami  tliu  digastric,  inylo-hyoid,  geuio-hyoid,  and 
genio-hyo-fjlossus  muscles.  Tliis  displacement  allows  the  base  of  the  tongue  to 
fall  against  the  epiglottis,  and  thus  asphyxiation  may  be  produced. 


SURFACE  ANATOMY  OF  THE  CRANIUM. 

The  Cranium  is  that  poi'tion  of  the  head  which  extends  from  the  lower 
margin  of  the  forehead  in  front  to  the  upper  extremity  of  the  neck  behind, 
from  ear  to  ear  laterally,  and  along  the  base  of  the  brain-case  below. 
The  base  of  the  brain-case  is  represented  by  a  line  which  extends  from 
the  eyebrows,  througli  the  external  auditory  meatus,  to  the  najie  of  the 
neck.  The  covering  of  this  area,  with  the  exception  of  that  of  the  fore- 
head   and    part    of  tlie    temporal    regions,    constitutes    the    scalp. 

The  Scalp  is  covered  by  hair,  which  is  more  or  less  abundant.  At 
the  junction  of  the  middle  and  posterior  thirds  of  the  sagittal  suture  can 
be  seen  a  dividing  point  of  the  hair,  from  which  it  falls  radially  in  all 
directions.  It  is  at  this  jwint  that  baldness  usually  begins.  The  density 
of  tiie  scalp  is  well  marked.  The  integument  is  closely  connected  with 
the  cranial  or  occipito-frontalis  aponeurosis,  on  account  of  which  attachment 
many  persons  can  readily  move  the  scalp  by  the  alternate  contractions  of 
the  occipital  and  frontal  divisions  of  the  muscle.  The  scalp  is  lacking  in 
elasticity,  especially  in  the  back  part.  In  peeling  the  scalp  back,  during 
postmortem  examinations,  it  sometimes  tears,  and  in  the  subsequent  sewing 
stitches  pull  tln'ongh  if  drawn  very  tightly.  In  this  respect  the  scalp 
differs  remarkal^ly  from  the  skin  of  other  regions  of  the  bod}'.  The  skin  else- 
where has  more  elasticitv  and  allows  much  stretching  before  it   tears.     Tumors 


588  SURGICAL  ANATOMY. 

of  the  scalp  are  movable  if  above  the  cranial  aponeurosis ;  when  below  it  they  are 
immovable. 

The  arteries  of  the  scalp  are  the  frontal,  which  ascends  near  the  median  line ; 
the  supra-orbital,  which  is  found  above  the  supra-orbital  notch  and  for  some 
distance  up  the  forehead  ;  the  anterior  branch  of  the  temporal  artery  (often  very 
tortuous),  found  about  one  and  one-quarter  inches  behind  the  external  angular 
process  of  the  frontal  bone ;  the  posterior  branch  of  the  temporal,  which  runs 
above  and  in  front  of  the  ear  ;  the  posterior  auricular,  above  and  behind  the  ear  ; 
and  the  occipital,  distinguishable  about  midway  between  the  mastoid  process  and 
the  external  occipital  protuberance. 

In  examining  the  head  as  a  whole,  it  will  be  noticed  that  the  two  sides  are 
not  symmetric — one  side  almost  always  having  larger  dimensions  than  the  other. 
Although  the  general  conformation  of  the  skull  cap  is  a  fair  index  of  its  contents, 
it  does  not  follow  that  every  minute  change  in  form  of  the  brain  has  its  effect  upon 
the  skull,  as  is  claimed  by  many  phrenologists. 

The  cranial  bones  are  the  frontal,  tAvo  parietal,  two  temporal,  the  occipital, 
the  sphenoid,  and  the  ethmoid.  In  the  adult  they  are  immovably  connected  with 
one  another,  the  lines  of  their  junctions  being  termed  sutures.  In  infancy  the 
frontal  bone  consists  of  two  portions ;  these  coalesce  very  early  in  life,  the  line  of 
union  being  the  frontal  suture.  The  two  parietal  bones  are  joined  by  the 
sagittal  suture.  Tlie  course  of  the  two  sutures,  the  frontal  and  sagittal, 
corresponds  to  a  line  drawn  from  the  root  of  the  nose,  directly  backward  over  the 
median  line  of  the  vault  of  the  skull,  to  the  external  occipital  protuberance.  In 
this  line,  within  the  skull,  are  the  .superior  longitudinal  sinus  and  the  longitudinal 
fissure  of  the  cerebrum.  The  parietal  bones  are  joined  to  the  frontal  bone  by  the 
coronal  suture,  and  to  the  occipital  bone  by  the  lambdoid  suture.  About  one  inch 
anterior  to  tlie  center  of  a  vertical  line  drawn  directly  over  the  skull  from  one  exter- 
nal auditory  meatus  to  the  other,  and  at  the  junction  of  the  coronal  with  the  sagittal 
suture,  is  the  bregma,  which  is  the  situation  of  the  anterior  fontanel  of  the  infant. 
The  coronal  suture  corresponds  to  a  line  drawn  from  the  bregma  to  the  middle  of 
the  zygomatic  arch.  The  lambdoid  suture  is  represented  by  a  line  drawn  from  tlie 
posterior  border  of  the  base  of  the  mastoid  process  to  a  point  midway  between  the 
bregma  and  the  external  occipital  protuberance.  The  lambda  is  the  point  of 
junction  of  the  sagittal  and  lambdoid  sutures.  This  is  the  .site  of  the  posterior 
fontanel  in  infants.  The  pterion — the  junction  of  the  anterior  inferior  angle  of 
the  parietal,  the  frontal,  tlni  tciniioral,  and  the  greater  wing  of  the  sphenoid  bone 
— is  found  about  one  and  one-half  inches  behind  the  external  angular  process  of 
the  frontal  bone,  and  about  the  same  distance  above  the  zygoma. 

The  superciliary  ridges  commence  on  each  side  of  the  glabella,  which  is 


PLATE  CXLVl. 


Iregma 


CRANIAL  LANDMARKS  AND   LINES  OF  CEREBRAL  FISSURES. 
589 


SURFACE  ANATOMY  OF  THE   CRANIUM.  591 

the  elevation  above  the  root  of  the  nose,  and  extend  outward  in  a  gentle  curve, 
gradually  becoming  less  prominent.  The  superciliary  ridges  mark  the  location  of 
the  sinuses  of  the  frontal  bone,  but  may  vary  greatly,  generally  because  of  the 
difference  in  size  of  tlie  frontal  sinuses.  They  are  small  in  females  and  absent  in 
children.  Although  the  size  of  the  ridge  may  be  an  indication  of  the  size  of  the 
frontal  sinus,  yet  this  does  not  always  hold  good,  as  we  may  find  a  large  ridge  with 
but  little  development  of  the  sinus ;  and  vice  versa.  Some  of  the  Australian  abor- 
igines have  very  small  sinuses,  but  large  ridges,  due  to  great  thickness  of  the  bone. 

Above  the  superciliary  ridges  are  found  the  frontal  eminences.  They  are 
slightly  convex  elevations  wliich  mark  tlie  original  centers  of  ossification  in  the 
two  frontal  bones.  Their  prominence  is  generally  considered  as  an  index  of  the 
amount  of  intellectual  capacity  of  the  individual.  The  increase  in  the  develop- 
ment of  the  skull  as  a  whole  causes  the  frontal  bones  to  become  upright,  and  thus 
makes  the  frontal  eminences  more  prominent. 

Immediately  behind  the  external  ear  is  the  mastoid  process  of  the  temporal 
bone.  It  is  but  rudimentary  in  infancy,  and  develops  later  in  life.  It  extends 
downward  for  about  an  inch  below  the  external  auditory  meatus,  and  projects 
forward  slightly  under  it.  The  digastric  fossa  is  internal  to  the  mastoid  process. 
The  body  of  the  process  is  honeycombed  witli  air-cells,  which  are  connected  with  the 
middle  ear.  At  times  these  become  so  inflamed  that  trephining  or  incision  is 
necessary  to  afford  relief.  The  incision  should  be  made  in  the  hairless  space  behind 
the  ear  (Wilde's  incision).  A  line  connecting  the  tips  of  the  two  mastoid  processes 
would  pass  through,  or  immediately  under,  the  condyles  of  the  occipital  bone. 

About  half  an  inch  above  and  three-quarters  of  an  inch  behind  the  posterior 
border  of  the  mastoid  process  is  the  asterion — the  junction  of  the  lambdoid  and 
squamous  sutures. 

The  external  occipital  protuberance  (inion)  is  distinctly  felt  in  the  median 
line  at  the  posterior  part  of  the  head,  at  the  junction  of  the  skin  of  the  neck  with 
that  of  the  head.  It  is  the  thickest  part  of  the  vault  of  the  skull.  From 
it  the  superior  curved  lines  of  the  occipital  bone  extend  laterally  and  give 
attachment  to  some  of  the  muscles  which  support  the  head.  The  external 
occipital  protuberance  marks  the  position  of  the  torcular  Herophili,  or  the  con- 
fluence of  the  superior  longitudinal,  two  lateral,  straight,  and  occipital  sinuses. 
Above  the  superior  curved  lines  the  general  contour  of  the  .skull  can  be  readilj' 
seen,  as  the  covering  is  composed  of  thin  structures.  Below  these  lines,  however, 
the  skull  recedes  to  a  considerable  extent,  the  space  being  filled  in  with  the 
strong  muscles  and  fascige  of  the  neck.  In  the  region  of  the  occiput  there  is 
occasionally  found  a  bulging  of  the  membranes  of  the  brain  (meningocele),  or  of 
the  brain  itself  (encephalocele) ;  in  these  cases  there  is  defective  ossification  of  the 


592  SURGICAL  ANATOMY. 

occipital  bone,  and  the  tumor  caused  by  the  protruding  cranial  contents  is  always 
in  the  median  line. 

The  parietal  eminences  which  mark  the  position  of  the  centers  of  ossification 
in  the  parietal  bones  are  readily  distinguishable  on  the  sides  of  the  skull  aljove  the 
ears.  They  are  much  more  marked  in  infancy,  gradually  becoming  rounded  and 
less  prominent.  Anterior  to  the  parietal  eminences,  and  running  along  the  sides  of 
the  head,  are  the  two  temporal  ridges  which  limit  the  temporal  fossa)  above  and 
give  attachment  to  the  temporal  fascia.  They  commence  at  the  external  angular 
process  of  the  frontal  bone  and  arch  upward,  backward,  and  then  downward,  to 
become  lost  on  the  posterior  roots  of  the  zygomatic  process.  The  point  where  the 
coronal  suture  is  crossed  by  the  temporal  ridge  is  known  as  the  stephanion.  It  is 
about  one  and  one-quarter  inches  above  the  pterion. 

The  middle  meningeal  artery  passes  upward  on  the  anterior  inferior  angle  of 
the  parietal  bone,  and  is  found  by  trephining  an  inch  and  a  half  behind  and 
about  an  inch  above  the  external  angular  process. 

The  course  of  the  superior  longitudinal  sinus  is  indicated  by  a  line  drawn 
over  the  median  line  of  the  top  of  the  head,  or  from  the  root  of  the  nose  to  the 
external  occipital  protuberance. 

The  course  of  the  horizontal  portion  of  the  lateral  sinus  is  shown  by  the 
posterior  part  of  a  line  drawn  from  the  external  occipital  protuberance  to  a  point 
one  inch  above  the  external  auditory  meatus.  The  sinus  turns  downward  and 
becomes  the  sigmoid  sinus  at  the  point  where  a  vertical  line  drawn  through  the 
posterior  border  of  the  base  of  the  mastoid  process  crosses  the  line  for  the  horizontal 
portion. 

The  course  of  the  sigmoid  sinus  is  marked  by  a  line  dra-mi  from  the  point 
of  termination  of  the  horizontal  portion  of  the  lateral  sinus  to  the  tip  of  the 
mastoid  process. 


SUBFACE  ANATOMY  OF  THE  FACE. 

The  appearance  of  the  face  in  health  and  disease  deserves  attention  from  the 
physician.  In  infancy,  owing  to  greater  abundance  of  subcutaneous  fat  and  the 
lack  of  development  of  the  muscles  of  expression,  the  face  is  full  and  round  ;  the 
relatively  greater  development  of  the  brain  and  sense  organs  causes  the  upper 
portion  of  the  face  to  be  broader  than  the  lower  ;  the  nasal  fossae  are  shallow,  and 
the  maxillary  bones  are  small. 

In  old  age  the  subcutaneous  fat  largely  disappears  and  the  integument 
becomes   wrinkled   and   thinner.     Not   infrequently  there   are  observed  areas  of 


SURFACE  ANATOMY  OF  THE  FACE.  593 

thickeiu'd,  browiiisli  c']ii(lornus  (keratosis  senilis),  particularly  in  persons  much 
exposed  to  the  weather.  After  middle  life  there  is  a  tendency  to  dilatation  of  the 
superficial  vessels,  especially  on  the  nose  and  cheeks. 

The  absorption  of  the  alveolar  processes  and  loss  of  the  teeth  cause  the  charac- 
teristic aiipearance  of  the  mouth  in  old  age  ;  the  lips  being  inverted,  the  red  border 
becomes  narrt)\\er,  i\nd  when  the  mouth  is  closed  the  chin  is  drawn  toward  the 
nose. 

The  more  or  less  characteristic  changes  produced  by  disease  can  not,  of  course, 
be  described  here  ;  allusion  may  be  made  to  the  waxy  hue  of  the  skin  in  certain 
renal  affections,  the  cyanosis  in  grave  cardiac  lesions,  the  hectic  flush  associated 
with  J lulmonary  tuberculosis,  and  the  "  facies  hippocratica."  In  the  last  named 
the  sunken  temples  and  cheeks  ;  the  pointed  nose  and  chin  ;  the  dull,  leaden  hue ; 
the  few  drops  of  perspiration,  and  the  cold,  clammy  skin  portend  the  near 
approach  of  death. 

The  supra-orbital  arches  are  readily  recognized  as  the  dividing  line  between 
the  forehead  and  the  face.  They  are  strong  arches  which  form  the  upper 
boundary  of  the  circumference  of  the  orbit.  They  are  covered  by  the  eyebrows. 
Internally  they  end  in  the  internal  angular  ])rocesses  of  the  frontal  bone,  which 
articulate  with  the  lacrymal  bone  and  the  nasal  process  of  the  superior  maxilla. 
Between  the  two  internal  angular  processes,  at  tlie  fronto-nasal  suture,  a  meningo- 
cele or  an  encephalocele  sometimes  appears.  Externally,  the  supra-orbital  arches 
terminate  in  the  external  angular  processes,  which  articulate  with  the  malar  bone. 
Immediately  below  the  supra-orbital  arches  are  the  eyes.  They  and  their  lids 
present  points  of  interest.  In  size  the  eyes  do  not  vary  much  in  different  indi- 
viduals, the  apparent  difference  being  due  to  the  variations  in  the  length  of  the 
palpebral  fissure,  which  thus  permits  a  larger  or  smaller  portion  of  the  ocular 
surface  to  come  into  view.  The  palpebral  fissure  is  the  aperture  between  the 
edges  of  the  two  lids,  and  extends  from  the  inner  to  the  outer  canthus.  The  fissure 
is  not,  as  a  rule,  exactly  horizontal,  the  outer  canthus  being  generally  a  little 
higher  than  the  inner. 

By  everting  the  eyelids,  the  tarsal  cartilage  may  be  felt  as  a  thickened 
portion  of  the  lid.  The  vertical  arrangement  of  the  Meibomian  glands  in  the 
tarsal  cartilage  can  also  be  made  out.  During  sleep  the  eyeball  turns  upward  and 
inward,  thus  sheltering  the  pupil  behind  the  base  of  the  upper  lid  under  the  supra- 
orbital arch,  the  lower  lid,  at  the  same  time,  moving  upward  and  somewhat 
inward.  In  fainting  sjjells,  or  during  sleep,  the  white  sclerotic  of  the  eyeball 
shows  through  the  jialpebral  fissure.  This  ftict  is  often  of  value  in  detecting  a 
sham  sleep  or  a  sham  faint ;  when,  after  gently  lifting  the  upper  lid  by  pressing 
upward  and  against  the  eyeball,  if  the  pupil  is  in  view,  the  patient  is  not  asleep. 

S— 38 


594  SURGICAL  ANATOMY. 

The  puncta  lachrymalia  are  readilj^  discernible  near  the  inner  canthus,  the 
lower  being  the  larger  and  more  external.  The  introduction  of  a  probe  into  the 
lacrj'inal  canaliculus  should  be  preceded  by  drawing  the  lid  outward,  thus 
straightening  the  canal. 

The  tendo  oculi  can  be  felt  after  drawing  the  eyelids  outward,  or  forcibly  clos- 
ing the  eye.  Immediately  behind  this  is  the  lacrymal  sac.  If  a  knife  were  pushed 
backward  just  below  tlie  tendo  oculi  it  would  enter  the  sac,  with  the  angular 
artery  and  vein  on  the  inner  side  of  the  puncture.  A  probe  passing  through  this 
opening  into  the  sac,  and  then  downward,  slightly  outward,  and  backward,  would 
enter  the  nasal  duct  and  appear  in  the  inferior  meatus  of  the  nose.  Tension  upon 
the  tendon,  as  in  closure  of  the  eyelids,  compresses  the  sac,  with  which  it  is  closely 
connected,  thus  emptying  the  sac  and  forcing  the  tears  which  have  collected  at  the 
inner  angle  of  the  eye  down  the  nasal  duct. 

The  nasal  duct  extends  from  the  inner  angle  of  the  eye  to  the  inferior  nasal 
meatus,  just  under  the  inferior  turbinated  bone.  It  is  about  three-quarters  of  an 
inch  in  length,  and  constricted  in  its  middle.  The  lower  opening  in  the  nasal 
mucous  membrane  is  a  slit,  luit  there  is  cjuite  a  large  opening  in  the  dry  bone. 
When  the  lower  end  of  the  duct  lies  in  the  lateral  wall  of  the  meatus  instead 
of  in  its  roof,  greater  difficulty  is  experienced  in  passing  a  probe  into  the  duct. 

The  lower  border  of  the  orbit  (infra-orbital  margin)  lies  immediately  below 
the  eyeball  and  is  formed  by  the  superior  maxillary  and  malar  bones.  It  can 
be  readily  felt  throughout  its  entire  extent. 

The  glabella  is  a  flat,  triangular  eminence  situated  between  the  two  internal 
extremities  of  the  superciliary  ridges.  Immediately  below  the  apex  of  the  glabella 
is  found  the  prominence  of  the  nose  formed  by  the  nasal  bones. 

The  form  of  the  nose  and  much  of  the  general  expression  of  the  face  are  due 
to  the  size  and  form  of  the  nasal  bones.  The  difference  in  these  bones  accounts  for 
the  variations  we  find  in  the  various  races.  In  the  Mongolian  and  Ethiopian  the 
nasal  bones  are  flat  and  broad  at  their  base,  and  thus  form  the  flat  nose  which  is 
so  characteristic  of  those  races.  In  the  Caucasian  race,  however,  the  nasal  bones 
are  narrow  and  elongated  as  well  as  prominent  at  the  bridge.  The  nose  is  rigid  at 
its  root  and  base  as  far  as  its  middle,  beyond  which  it  is  cartilaginous  and  flexible. 
The  intimate  adherence  of  the  skin  to  the  nasal  cartilages,  which  are  attached  to 
the  lower  ends  of  the  nasal  bones,  makes  furuncles  or  erysipelas  in  this  region 
exceedingly  painful,  liecau.se  of  the  lack  of  cutaneous  elasticity. 

The  lower  end  (if  the  nose  is  open  and  dividcil  into  the  two  anterior  nares  by 
tlie  nasal  septum  and  the  coluwna.  It  .should  not  be  forgotten  that  the  nose  is 
attached  lower  than  the  floor  of  its  cavity  ;  so  that  it  must  be  elevated  when  the 
interior  is  to  be  inspected. 


SURFACE  ANATOMY  OF   THE  FACE.  595 

Below  the  nose  is  seen  the  mouth,  which  is  the  upper  opening  of  the  gastro- 
intestinal tract.  The  lips  contain  muscles  and  vessels,  and  play  a  large  part  in  the 
general  expression  of  the  face.  In  the  living  suhjcct  the  pulsations  of  the  superior 
and  inferior  coronary  arteries  can  be  easily  felt  by  holding  the  lips  between  the 
finger  and  the  thumb.  In  the  operation  for  harelip  these  arteries  are  divided, 
the  ensuing  hemorrhage  being  easily  controlled  by  pressure  with  the  finger  and 
thumb.  Although  the  aperture  between  the  lips  is  generally  spoken  of  as  the 
mouth,  it  must  be  remembered  that  the  mouth  extends  backward  from  the  lips  to 
the  pharynx. 

Below  the  lips  can  be  found  the  prominence  of  the  symphysis  of  the  lower 
jaw.  The  lower  jaw  is  easily  felt  from  the  symphysis  to  the  condyle,  where 
it  articulates  with  the  temporal  bone.  By  slight  pressure  along  the  bone 
the  alveolar  border,  in  which  the  teeth  are  set,  can  be  readily  distinguished.  In 
passing  the  finger  backward  along  the  lower  border  of  the  body  of  the  jaw  the 
angle,  which  is  at  the  junction  of  the  body  with  the  ramus,  can  be  distinguished. 
In  front  of  the  angle  is  a  depression  through  which  passes  the  facial  artery,  the 
pulsation  of  which  can  be  detected  in  the  living  subject.  The  condyle  of  the  lower 
jaw  is  felt  in  front  of  the  tragus  of  the  external  ear  and  below  the  zj'gomatic  arch. 
When  the  mouth  of  a  living  person  is  opened,  the  condyle  can  be  felt  leaving  the 
glenoid  fossa  and  advancing  upon  the  eminentia  articularis.  This  forward 
motion  of  the  condyle  affords  a  freer  access  to  the  external  ear,  which  can  be 
demonstrated  by  passing  the  little  finger  into  the  external  auditory  meatus  and 
opening  and  closing  the  mouth. 

In  the  supra-orbital  margin,  at  the  junction  of  its  inner  with  its  middle  third, 
is  the  supra-orbital  notch,  or  foramen,  which  gives  passage  to  the  supra-orbital 
vessels  and  nerve.  The  mental  foramen  is  found  in  the  lower  jaw,  opposite  the 
second  bicuspid  tooth  ;  it  gives  pas.sage  to  the  mental  vessels  and  nerve.  In  a  line 
drawn  between  the  supra-orbital  notch  and  mental  foramen,  and  just  below  the 
infra-orbital  margin,  is  the  infra-orbital  foramen,  which  gives  passage  to  the  infra- 
orbital vessels  and  nerve.  These  nerves  are  derived  from  the  fifth  cranial  nerve. 
Quite  frecjuently  accessor}'  foramina  are  found  external  to  the  constant  ones,  and 
usually  transmit  a  portion  of  the  nerve  which  commonly  passes  through  the 
normal  foramen.  These  anomalies,  especially  on  account  of  their  frequency,  are 
of  considerable  significance  in  the  treatment  of  neuralgias  by  nerve  section.  The 
•anomalous  openings  occur  most  frequently  in  connection  witli  the  supra-orbital,  the 
infra-orbital,  or  the  mental  foramen,  in  the  order  named,  and  upon  the  right  side. 
At  times  a  deep  groove  extends  for  several  inches  upward  from  the  accessory  supra- 
orbital foramen  and  about  a  finger's  breadth  internal  to  the  temporal  ridge. 
Failure  to  obtain  relief  in  some  cases  of  neuralgia,  after  section  of  the  nerve  which 


596  SURGICAL   ANATOMY. 

passes  through  the  normal  foramen,  may  be  due  to  an  accessory  nerve,  instead  of 
to  central  disease  or  affections  of  the  ganglia  connected  with  the  parent  stem. 

Continuing  outward  from  the  external  angular  process  is  the  zygomatic  arch, 
formed  by  the  malar  bone  and  the  zj'gomatic  process  of  the  teniiporal  bone.  The 
anterior  part  of  the  arch  is  flat  and  broad,  and  forms  the  prominence  of  tlie  cheek, 
or  the  "  cheek  bone."  Posteriorly,  the  zygomatic  arch  terminates  in  front  of,  and 
just  above,  the  external  auditory  meatus.  On  account  of  the  attachment  of  the 
dense  temporal  fascia  to  the  upper  border  of  this  arch,  the  lower  border  is  more 
easily  distinguished.  The  zygomatic  arch  forms  a  dividing  line  between  two 
depressions.  These  are  generally  filled  with  fat  in  the  healthy  individual,  and, 
therefore,  are  not  markedly  evident.  As  soon  as  a  wasting  disease  begins  to  tax 
the  organism,  the  fat  above  the  zygoma  is  absorbed,  and  this  bony  arch  becomes 
much  more  prominent ;  as  the  wasting  progresses,  the  masseteric  depression  can  be 
plainly  seen,  and,  at  the  same  time,  the  fat  in  front  of  the  anterior  margin  of  the 
masseter  muscle  and  below  the  anterior  half  of  the  malar  bone  disapfjcars,  with 
resultant  sinking  of  the  cheeks. 

The  arteries  of  the  face  are  the  temporal,  between  the  ear  and  zygoma,  and 
the  facial,  on  the  body  of  the  lower  jaw  just  in  front  of  the  masseter  muscle,  at  the 
angle  of  the  mouth,  and  passing  along  the  naso-labial  fold  and  side  of  the  nose  to 
the  inner  angle  of  the  eye.  The  facial  A^ein  runs  straight  across  the  face  from  the 
inner  canthus  of  the  eye  to  the  anterior  inferior  angle  of  the  masseter  muscle  at 
the  lower  border  of  the  lower  jaw..  The  anterior  temporal  and  facial  arteries  are 
useful  to  the  anesthetizor  in  studying  the  pul.se,  and  also  to  the  physician  when 
the  patient  is  sleeping. 

Expression  is  due  to  muscular  traction  upon  the  facial  integument.  In  facial 
hemiplegia,  when  the  muscles  of  the  affected  side  have  lost  their  power,  expres- 
sion is  gone,  and  the  wrinkles  of  the  face  disappear.  The  "  expression  of  the  eye  " 
is  due  to  wrinkling  of  the  lids  and  the  peri-ocular  integument.  The  study  of  the 
relation  between  facial  expression  and  the  permanent  markings  of  the  face  resulting 
therefrom,  as  an  index  to  character  and  disposition,  is  still  in  its  infancy.  Note  the 
proximity  of  the  muscle  centers  of  the  face  in  the  ascending  frontal  and  parietal 
gyri  to  the  speech  center.  The  latter  is  at  the  tip  of  the  operculum  around  the 
ascending  arm  of  the  Sylvian  fissure,  and  at  the  lower  part  of  the  ascending  gyri. 
Just  above  it  is  the  lip  center,  followed  by  that  of  the  face,  fingers,  hand,  and  arm, 
with  that  of  the  lower  limb  overtopping  all.  Is  this  not  also  the  order  in  which 
these  muscle  groups  arc  involved  during  increasing  animation  accompanying  a  dis- 
cussion ?  The  central  excitement  becomes  greater  and  extends  over  wider  areas, 
sending  larger  and  more  intense  impulses  to  those  muscle  bundles  which  traverse 
the  facial  integument  and  jjuU  its  surface  hither  and  thither,  forming  wrinkles, 


PLATE  CXLVII 


INCISIONS  FOR   DISSECTION. 
597 


PLATE  CXLVIIL 


Artery  in  superficial  fascia 


1 1\  I 


Skin        Superficial  fascia 


^ 


Occipito-frontalis  aponeurosis' 
Areolar  tissue 


Outer  table  of  skull      Diploe    /  Dura  mater 

Inner  table  of  skull 

LAYERS  OF  SCALP. 


( 


I 


CIRSOID  ANEURYSM. 
599 


SCALP.  601 

dimples,  scowls,  and  )iuckorinc;s,  oxpivssivo  of  (lu'  (■(iii(li(i<m  of  ilu;  niiml  in 
relation  to  tho  matter  engaging  it.  The  hnbilual  rc-currcm'c  of  these  emotioiKil 
resnlts  leaves  its  impress  by  gradually  undeniiining  tlie  elasticity  of  the  skin 
involved  and  by  contracting  the  atfected  muscles,  producing  upon  the  individual's 
face  indications  of  his  character  which  may  be  read  by  all  who  are  competent. 

The  external  ear,  or  pinna,  is  placed  at  the  junction  of  the  face,  neck,  and 
cranial  vault.  Tiie  general  conformation  and  dii-cctioii  of  the  [liniia,  and  its  ntilifv 
for  the  collection  and  partial  condensation  of  sound,  need  only  bo  mentioned. 
During  inspection  of  the  tympanic  membrane  and  of  the  wliolc  length  of  the  exter- 
nal auditory  canal,  the  direction  of  the  latter  concerns  us  practically.  It  is  al)out 
an  inch  and  a  quarter  long,  ^\■hen  removing  foreign  bodies,  wliich  frequently 
lodge  in  this  canal,  it  is  imi)ortant  to  note  that  it  sags  at  its  outer  end,  and  can  be 
straightened  l)y  pulling  the  pinna  uj)war<l.  The  greatest  diameter  of  the  canal  is 
vertical  at  the  external  end,  and  transverse  at  the  internal.  The  ui)per  and 
posterior  portions  of  the  tympanic  membrane  incline  outward. 


SCALP. 

Dissection. — The  dissection  of  the  scalp  should  be  made  before  that  of  the 
face  and  neck.  The  body  should  lie  on  its  back,  the  head  being  well  elevated  by 
means  of  a  large  block  placed  under  the  nape. of  the  neck.  The  head  having 
been  shaved,  an  incision  should  be  carried  from  the  root  of  the  nose  over  the 
middle  line  of  the  vertex  to  the  external  occipital  protuberance ;  and  a  second 
incision,  at  a  right  angle  to  the  iir.st,  commencing  at  the  nasal  eminence,  should 
extend  on  each  side  as  far  back  as  the  ear.  Beginning  at  the  junction  of  the 
two  incisions,  reflect  the  skin  backward  and  outward,  forming  two  flaps.  AMien 
dissecting  these  flaps  great  care  must  be  taken  to  remove  only  the  skin,  the  l)est 
guide  being  the  bulbs  of  the  hair,  which  are  in  the  superficial  fascia. 

The  scalp  is  that  portion  of  the  cranial  covering  which  lies  in  front  of  the 
superior  curved  ridges  of  the  occipital  bone  and  above  the  two  temporal  ridges, 
though  in  the  dissection  of  the  scalp,  for  convenience,  the  tissues  in  the  temporal 
region  are  included. 

Layers. — The  scalp  above  the  temporal  ridges  is  made  up  of  five  layers — viz., 
skin,  superficial  fascia,  occipito-frontalis  aponeurosis,  loose  areolar  tissue,  and  ]ieri- 
cranium  (external  periosteum).  In  the  frontal  and  occipital  regions,  in  place  of  the 
aponeurosis,  are  the  muscular  bellies  of  the  occipito-frontalis  muscle.  Below  the 
temporal  ridges  (in  the  temporal  regions)  the  scalp  is  composed  of  eight  layers — 


602  SURGICAL  ANATOMY. 

viz.,  skin,  superficial  fascia,  attolens  and  attrahens  aurem  muscles,  occipito-fron- 
talis  (epicranial)  aponeurosis,  areolar  tissue,  temporal  fascia,  the  temporal  muscle, 
and  the  periosteum.  That  which  is  usuallj'  spoken  of  as  the  scalp  includes  the 
skin,  the  superficial  fascia,  and  the  occipito-frontalis  muscle  and  aponeurosis ;  these 
three  layers  are  closelj'^  adherent  to  one  another. 

The  skin  of  the  scalp  is  thicker  than  that  of  any  other  part  of  the  body.  By 
means  of  the  superficial  fascia  the  skin  is  closely  adherent  to  the  occipito-frontalis 
muscle  and  aponeurosis,  which  accounts  for  the  movement  of  the  skin  with  the 
muscle  and  its  aponeurosis.  It  is  rich  in  sebaceous  glands  which,  when  enlarged 
on  account  of  occlusion  of  their  ducts,  constitute  sebaceous  cysts  or  wens,  so 
common  in  this  region.  These  growths,  even  when  large,  except  in  very  rare 
instances,  are  superficial  to  the  occipito-fiontalis  aponeurosis,  and  with  care  can, 
therefore,  be  removed  without  risk  of  opening  the  areolar  tissue  layer.  The  skin  is 
well  nourished  by  the  vessels  of  the  superficial  fascia. 

The  superficial  fascia  of  the  scalp  consists  of  but  one  layer,  which  presents  a 
granular  appearance,  due  to  the  nodulated  fat  and  dense  fibrous  septa.  Its  septa 
firmly  connect  the  skin  to  the  occipito-frontalis  aponeurosis.  In  its  density  and 
capability  of  resisting  pressure  it  is  like  the  superficial  fascia  of  the  palm  of  the 
hand  and  sole  of  the  foot.  It  is  continuous  behind  with  the  sujjerficial  fascia 
of  the  back  of  the  neck ;  laterally,  and  in  front,  with  the  superficial  fascia  of 
the  face.  It  contains  the  principal  blood-vessels  and  nerves  of  the  scalp,  in 
tliis  respect  differing  from  the  superficial  fascia  elsewhere,  with  the  exception 
of  that  of  the  face  and  ischio-rectal  fossaB,  the  muscles  of  the  auricle,  and  the 
hair-bulbs.  The  arteries  of  the  scalp  lie,  as  it  were,  in  canals  in  the  fascia, 
and  are  attached  to  the  walls  of  these  canals  by  loose  fibrous  tissue ;  when 
divided,  they  have  a  slight  tendency  to  retract  within  these  channels  or  canals, 
and,  on  account  of  the  density  of  the  fascia,  it  may  be  difficult  to  seize 
them  with  the  arteiy  forceps.  Consequently,  some  form  of  pressure  is  often 
employed  to  check  the  bleeding.  The  presence  of  the  hair-bulbs  in  this- 
dense  fascia  and  their  firm  attachment  to  the  scalp  enable  a  strong  person, 
by  securely  grasping  the  hair,  to  lift  the,  entire  weight  of  the  body  without  tear- 
ing out  the  hair-roots.  Owing  to  the  density  of  the  superficial  fascia,  redness 
and  swelling  are  not  very  pronounced  in  inflammation  of  the  scalp.  The  super- 
firiiil  iiiscia  is  tliickest  in  the  occipital  region,  and  gradually  grows  tliinncr  as  it 
approaclios  the  front  and  sides  of  tlie  craiiium. 

Wounds  of  the  scalj)  bleed  freely,  because  the  arteries  can  not  contract  or 
retract  on  account  of  the  density  of  the  superficial  fiiscia  and  their  close  adherence 
to  the  connective-tissue  septa  within  which  they  ramify. 

DissKCTiox. — Upon  one  side  of  the  head  the  superficial  fascia  with  the  vessels 


PLATE  CXLIX, 


Anterior  temporal  <; 


Posterior  temporal  a. 


Supraorbital  a 
Frontal  a. 


Posterior  auricular  a 


Occipital  a. 


SUPERFICIAL  FASCIA  OF  SCALP. 
603 


SCALP.  605 

anil  nerves  arc  to  be  removed  as  one  com i  layer,  l)rin«;inji;  into  view  the  corre- 
sponding lialf  of  tlie  occipito-frontalis  aixineurosis  and  nnij^cle ;  wliile  ui)Mn  the 
other  side  only  the  sn]ierticial  fascia  in  the  innnediate  neiyhhnrliood  of  the  vessels 
and  nerves  is  to  be  removed,  in  this  way  exposing  and  giving  a  clear  idea  of  the 
blood  and  nerve  snjiply  of  the  scalp.  In  reflecting  the  suj)erficial  fiiscia  preserve 
the  attolens  and  attrahens  aiirem  muscles  which  lie  between  it  and  the  aponeurosis. 

The  Extrinsic  Muscles  of  the  Ear  are  very  feeble  and  rudimentary,  the 
auricle  in  man  being  practically  innnovalile.  Tiiey  aw  (line  in  number — the 
attolens  aurem,  attrahens  aurem,  and  retraliens  anrem  ;  they  reejuirc  considerable 
care  in  dissection  to  avoid  being  overlooked  and  destroyed. 

DissECTiox. — Draw  the  pinna  downward  and  fasten  it  with  hooks ;  this  will 
make  tense  the  attolens  and  attrahens  aurem  muscles. 

The  attolens  aurem,  the  largest  of  the  three  nmscles,  is  broad  and  fan-shaped, 
converging  to  a  narrow  tendon  below.  It  arises  from  the  superficial  surface  of  the 
occipito-frontalis  aponeurosis  below  the  temporal  ridge,  and  is  inserted  into  the 
cranial  aspect  of  the  upper  part  of  the  pinna. 

Nerve  Supply. — From  the  temporal  branch  of  the  facial  nerve. 

Action. — It  draws  the  pinna  upward. 

The  attrahens  aurem  is  the  smallest  muscle  of  the  three,  and  arises  from 
the  occii)ito-frontalis  aponeurosis  in  front  of  the  attolens  aurem  nuisele,  and  is 
inserted  into  the  front  of  the  helix. 

Nerve  Supply. — From  the  temporal  branch  of  the  facial  nerve. 

Action. — It  draws  the  pinna  forward  and  upward. 

Dissection. — Release  the  pinna  from  its  present  position  and  draw  it  forward  ; 
fasten  it  with  hooks,  and  divide  the  integument  over  the  tense  band  behind  the 
auricle  to  expose  the  retrahens  aurem  muscle. 

The  retrahens  aurem  muscle  consists  of  two  or  three  short  muscular  bundles 
which  arise  fi'om  the  mastoid  process  of  the  temporal  bone  and  are  inserted 
into  the  back  of  the  concha. 

Nerve  Supply. — From  the  posterior  auricular  branch  of  the  facial  nerve. 

Action. — It  draws  the  pinna  backward. 

The  Arteries  of  the  Scalp  are  derived,  in  front,  from  the  supra-orbital  and 
frontal  arteries ;  on  the  sides,  from  the  temporal  ;  and  behind,  from  the  posterior 
auricular  and  occipital  arteries. 

The  supra-orbital  artery,  a  lirancli  of  the  ophthalmie,  leaves  the  orljit 
through  the  .«upra-nrl)ital  notch,  and  divides  into  a  superficial  and  a  deep  branch, 
which  ascend  toward  the  vertex,  anastomosing  witli  the  temporal  ami  fiuntal  arte- 
ries and  with  the  supra-orljital  artery  of  the  opposite  side.  It  .supplies  the  tissues 
of  the  forehead. 


606  SURGICAL  ANATOMY. 

The  frontal  artery,  one  of  the  two  terminal  branches  of  the  ophthalmic, 
leaves  the  orbit  at  its  inner  angle  and  ascends  on  the  forehead,  anastomosing  with 
the  supra-orbital  and  with  the  frontal  artery  of  the  opposite  side. 

Tlie  temporal  artery,  the  smaller  of  the  two  terminal  divisions  of  the  exter- 
nal carotid,  commences  in  the  substance  of  the  parotid  gland  and  ascends  over  the 
posterior  root  of  the  zygoma,  about  two  inches  above  which  it  divides  into  the 
anterior  and  posterior  temporal ;  in  some  cases  it  divides  immediately  after  crossing 
the  zygoma  ;  rarely,  it  divides  below  the  zygoma.  It  is  accompanied  by  branches 
of  the  facial  and  auriculo-temporal  nerves.  It  is  covered  by  the  attrahens  aurem 
muscle  and  crossed  by  one  or  two  small  veins.  The  temporal  and  anterior 
temporal  arteries  are  the  vessels  used  by  the  anesthetizer  to  ascertain  the  character 
of  the  pulse. 

The  anterior  temporal  artery  passes  forward  in  a  tortuous  course  to  anas- 
tomose with  the  supra-orbital  and  frontal  arteries  and  with  the  anterior  temporal 
artery  of  the  opposite  side.  It  supplies  the  tissues  along  its  course.  It  is  the 
branch  usually  selected  when  blood  is  to  be  extracted  from  the  arterial  system. 

The  posterior  temporal  artery,  the  larger  of  the  two,  passes  upward  and 
backward  above  the  pinna  and  anastomoses  with  the  posterior  temporal  artery 
of  the  opposite  side  and  with  the  occipital  and  posterior  auricular  arteries. 

The  transverse  facial,  anterior  auricular,  and  middle  temporal  branches  of  the 
temporal  artery  will  be  described  with  the  dissection  of  the  face. 

The  posterior  auricular  artery  passes  over  the  mastoid  process,  and  divides  into 
two  branches — an  anterior  and  a  posterior.  The  anterior  branch  passes  forward 
and  anastomoses  with  the  posterior  temporal  artery ;  the  posterior  branch  passes 
backward  and  anastomoses  with  the  occipital  artery.  It  is  accompanied  by  the 
posterior  auricular  nerve,  a  branch  of  the  facial  nerve. 

The  occipital  artery  pierces  the  trapezius  muscle  at  its  attachment  to  the 
superior  curved  line  of  the  occipital  bone,  about  midway  between  the  mastoid 
process  and  the  external  occipital  protuberance.  Thence  it  ascends  in  a  tortuous 
course  over  the  back  of  the  head  to  the  vertex,  dividing  into  numerous  branches, 
Avliich  anastomose  with  the  occipital  artery  of  the  opposite  side  and  with  the  pos- 
terior temporal  and  posterior  auricular  arteries.  It  is  accompanied  by  the  great 
occipital  nerve. 

The  arteries  of  the  scalp  sometimes  become  elongated  and  tortuous,  producing 
what  is  known  as  cirsoid  aneurysm.  The  anterior  temporal  artery  is  the  one  most 
commonly  affected. 

Tlic  Veins  of  the  Scalp  accompany  the  corresponding  arteries,  with  the 
exce])tion  of  the  supra-orl)ital  and  frontal  veins,  which  unite  to  form  the  angular, 
the  commencement  of  the  facial,  vein.     The  veins  of  the  scalp  communicate  with 


PLATE  CL 


Supraorbital  a 
Frontal  a 


Orbital  a. 

Anterior  temporal  a. 

Posterior  temporal  a. 


Superior  coronary  a 


Stenson's  duct 


ARTERIES  OF  SCALP  AUG  FAOF, 
008 


PLATE  CLI. 


Temporal  br.  of  orbital  n 
Supraorbital  n. 


Infraorbital  br.  of  superior  maxillary  n. 


Mental  n. 
Infratrochlear  n 


Nasal  n. 


NERVES  OF  SCALP  AND  FACIAL  NERVE, 
609 


SCALP.  Gil 

the  sinuses  in  tlie  interior  of  tiie  skull  ;incl  witli  tlic  veins  of  the  diploe  by  means 
of  the  emissary  veins. 

The  Nerves  of  the  Scalp  are  branches  of  the  trifacial,  facial,  ami  great  occij)- 
ital  nerves,  and  of  the  cervical  j)lexus. 

The  supra-orbital  nerve,  the  larger  of  the  two  terminal  branches  of  the  frontal 
branch  nf  the  ophthalmic  nerve,  leaves  the  orbit  with  the  supra-orbital  artery 
through  the  supra-orbital  notch  or  foramen,  which  is  located  in  the  upper  margin 
of  the  orbit  at  the  junction  u'i  its  inner  and  middle  tliirds,  and  ascends  upon  the 
fniThead  beneath  the  orbicularis  palpebrarum  and  the  iVnntal  belly  of  the  occipito- 
frontalis  muscle.  It  divides  into  two  branches — an  inner  and  an  outer — and 
becomes  subcutaneous  ;  the  inner  branch,  the  smaller,  pierces  the  frontal  belly  of 
the  occipito-frontalis  muscle  and  ascends  as  high  as  the  parietal  bone ;  the  outer 
branch,  the  larger,  pierces  the  occipito-frontalis  aponeurosis  and  ascends  over  the 
vertex  as  far  as  the  occipital  bone. 

The  supra-trochlear  nerve,  the  smaller  of  the  two  terminal  branches  of  the 
frontal  branch  of  the  ophthalmic  nerve,  appears  at  the  inner  angle  of  the  orbit 
above  the  jaulley  of  the  superior  oblique  muscle,  and  ascends  upon  the  forehead. 
It  is  covered  by  the  orbicularis  palpebrarum  and  frontalis  muscles,  piercing  the 
latter  to  end  in  the  integument.  It  supplies  the  skin  of  the  forehead  and  the 
U]iper  eyelid. 

Neurectomy. — The  supra-orbital  and  supra-trochlear  nerves  are  often  affected 
by  neuralgia,  for  the  relief  of  which  division  or  resection  of  these  nerves  may  be 
required.  The  sujjra-orbital  notch,  if  present,  forms  a  sure  guide  to  the  position 
of  the  supra-orbital  nerve,  which  can  be  reached  and  exposed  by  a  vertical  incision 
immediately  over  the  notch,  or  by  a  transverse  incision  parallel  to  and  a  little 
below  the  e\'ebrow.  The  latter  method,  as  it  leaves  a  less  noticeable  scar,  is  the 
one  more  commonly  practised.  The  former  method,  however,  will  expose  a  larger 
portion  of  the  nerve.  The  skin  having  been  divided  by  either  a  vertical  or  a 
transverse  incision,  the  further  dissection  should  be  in  a  direction  parallel  to  the 
fibers  of  the  orbicularis  palpebrarum  muscle.  The  old  subcutaneous  operation  is 
now  seldom  done  on  account  of  the  extensive  extravasation  from  division  of  the 
sui>ra-orbital  vessels.  To  divide  the  nerve  well  back  in  the  orbit,  it  is  necessary  to 
sever  the  orbito-tarsal  ligament  and  depress  the  orbital  fat,  when  the  nerve  is  sepa- 
rated from  its  connections  and  lifted  on  a  blunt  hook.  The  supra-trochlear  ner\'e 
is  exposed  through  an  incision  carried  in  a  line  drawn  from  the  angle  of  the  mouth 
through  and  beyond  the  inner  canthus.  The  nerve  will  be  found  at  the  point 
of  intersection  of  this  line  with  the  upper  margin  of  the  orbit  The  occasional 
presence  of  an  accessory  supra-orbital  foramen,  giving  passage  to  a  division 
of    the   supra-orbital   nerve,    should    not   be    overlooked.      Recurrence   of   pain 


612  SURGICAL  ANATOMY. 

immediately  after  operation  is  good  presumptive  evidence  of  the  existence  of 
an  accessory  foramen. 

Temporal  branch  of  the  orbital  nerve. — About  an  inch  above  the  zj'goma 
the  temporal  fascia  is  pierced  by  tlic  temporal  branch  of  the  orbital  branch  of  the 
superior  maxillary  nerve,  which  is  distributed  to  the  integument  of  the  temjile 
and  communicates  with  the  temporal  branch  of  the  facial  nerve. 

The  auriculo-temporal  nerve,  a  branch  of  the  inferior  maxillarj'  nerve, 
accompanies  the  temporal  vessels,  lying  posterior  to  tlicm.  The  auriculo-temporal 
nerve  emerges  from  beneath  the  upper  part  of  the  parotid  gland,  and  divides  into 
two  terminal  branches — the  anterior  and  posterior  temporal.  The  anterior 
temporal  nerve,  the  larger,  accompanies  the  anterior  temporal  artery  to  the 
vertex,  and  communicates  with  the  facial  and  temporo-malar  nerves.  The 
posterior  temporal  nerve,  the  smaller,  accompanies  the  posterior  temporal  artery. 

Temporal  branches  of  the  facial  nerve  extend  upward  over  the  zygoma  upon 
the  temple  to  supply  the  attrahens  and  attolens  aurem,  the  orbicularis  palpe- 
brarum, the  frontalis,  and  the  corrugator  supercilii  muscle.  They  communicate 
with  the  temporo-malar,  auriculo-temporal,  lacrymal,  and  supra-orbital  nerves. 

The  posterior  auricular  nerve,  a  branch  of  the  facial,  accompanies  the 
posterior  auricular  artery,  and,  like  the  latter,  divides  into  two  branches — a 
posterior  and  an  anterior.  The  posterior  (occipital)  supplies  the  occipitalis  muscle ; 
the  anterior  (auricular),  the  auricle  and  the  retrahens  and  attolens  aurem  muscles. 
This  nerve  is  joined  by  filaments  from  the  auricular  branch  of  the  pneumogastric 
nerve  and  from  the  great  auricular  and  small  occipital  nerves. 

The  small  occipital  nerve  (occipitalis  minor),  a  branch  of  the  anterior  division 
of  the  second  cervical  nerve,  supplies  the  scalp  behnid  the  car  and  over  the  occiput. 
It  communicates  with  the  great  auricular  and  the  great  occipital  nerve,  and  with 
the  posterior  auricular  branch  of  the  facial  nerve.  It  can  be  seen  in  the  neck 
running  along  the  posterior  border  of  the  sterno-mastoid  muscle. 

The  great  occipital  nerve  (occipitalis  major),  the  largest  cutaneous  nerve  of 
the  scalp,  accompanies  the  occipital  artery  over  the  occij)ut.  It  is  the  internal 
branch  of  the  posterior  division  of  the  second  cervical  nerve ;  pierces  the  com- 
plexus  and  trapezius  muscles  near  their  attachment  to  the  occipital  bone  ;  enters 
the  superficial  fascia  with  the  occipital  artery,  and  breaks  up  into  a  number  of 
large  branches  which  spread  over  the  back  of  the  head,  supplying  the  integument 
as  fiir  forward  as  tlie  vertex.  It  communicates  with  the  small  occipital  and  the 
first  cervical  nerve,  and  receives  a  branch  from  the  tliird  cervical  nerve. 

The  Lymphatics  of  the  Scalp  follow  the  same  course  as  the  blood-vessels, 
which  is  the  general  rule.  Tlie  j)osterior,  or  occi])ital,  lymphatics  enter  the 
occipital  glands  situated  along  the  origin  of  the  occipitalis  muscle ;  the  postero- 


PLATE  CLII. 


Malar  br.  of  facial  n 
Orbital  a, 
Temporal  br.  of  orbital  n 

Supraorbital  n. 

Supraorbital  a.  /M 


Transverse  facial  a. 

Temporal  br.of  facial  n. 


Posterior  temporal  a. 
Auriculo-temporal  n. 
Supcrfrcal  temporal  v. 


Supratrochlear  n 

Frontal  a 
Angular  a 


Occipital  a. 


Superior  coronary  a 

Inferior  coronary  a 

Inferior  labial  a 

Facial  a. 

Facial  V. 


Anterior  auricular  i 
Middle  temporal  a. 
Parotid  gland 
Supramaxillary  br.  of  facial  n. 
Stenson's  duct 


Buccal  br  of  facial  n. 
infraorbital  br.of  facial  n. 
Socia  parotidis 


ARTERIES,   NERVES,  AND  MUSCLES  OF  SCALP  AND  FACE. 
613 


SCALP.  G15 

lateral,  or  posterior  auricular,  set  enter  the  posterior  auricular  glands  situated  upon 
the  mastoid  attachment  of  the  sterno-mastoid  muscle ;  the  temi)oral  h-mphatics 
enter  the  glands  situated  upon  and  within  the  parotid  gland  ;  and  a  frontal 
set  end  in  the  facial  lymphatics.  In  congestion  of  the  scalp  due  to  cold,  and  in 
otiur  alU'ctions  of  tliis  region  -wliicli  increase  the  activity  of  the  lynipliatics,  these 
glands  are  considerably  swollen  and  painful. 

The  occipito-frontalis  muscle  and  ajioneurosis,  exposed  upon  the  side  from 
which  the  superficial  foscia  has  been  removed,  will  now  be  studied. 

The  occipito-frontalis  is  a  broad,  musculo-aponeurotic  layer  covering  one  side 
of  the  vertex  of  the  skull  from  the  occiput  to  the  l)row.  It  consists  of  two 
flattened  muscular  bellies,  an  occipital  and  a  frontal,  with  an  intervening  aponeu- 
rosis. 

The  ornpilnl  hclly  (occipitalis  muscle),  thin  and  quadrangular,  arises  from  the 
outer  two-thirds  of  the  superior  curved  ridge  of  the  occipital  bone  and  the 
adjoining  mastoid  process,  thus  leaving  a  triangular  interval  between  tlie  two 
occipitales  muscles  as  their  fibers  eventually  meet  higher  up  in  the  median 
line.  The  fibers  are  about  an  inch  and  a  half  in  length  and  ascend  to  the 
aponeurosis. 

Blood  Supply. — From  the  occipital  and  posterior  auricular  arteries. 

Nerve  Supply. — The  occipitalis  muscle  derives  its  nerve  supply  from  the 
posterior  auricular  branch  of  the  facial  and,  exceptionally,  from  the  occipitalis 
minor  nerve. 

The  frontal  belly  (frontalis  muscle),  a  thin,  muscular  layer  having  intimate 
cutaneous  connections,  arises  from  the  aponeurosis  below  the  coronal  suture.  It 
descends  over  the  forehead  and  blends  with  the  orbicularis  palpebrarum,  the  corru- 
gator  supercilii,  and  the  pj'ramidalis  nasi  muscle. 

Blood  Supply. — From  the  frontal,  supra-orbital,  and  anterior  temporal  arteries. 

Nerve  Supply. — The  frontalis  muscle  derives  its  nerve  supply  from  the 
temporal  branch  of  the  temporo-facial  division  of  the  facial  nerve. 

The  aponeurosis  extends  over  the  vertex  and  is  continuous  across  the  middle  line 
witli  the  aponeurosis  of  the  opposite  side  ;  laterally  it  is  continued  over  the  temporal 
fascia  to  the  zygoma,  just  above  which  it  is  attached  to  that  fascia.  Connected 
with  the  lateral  portion  of  the  aponeurosis  are  the  attolens  and  attrahens  aurem 
muscles.  It  is  intimately  connected  with  the  skin  through  the  attachment  of  the 
superficial  fascia,  and  but  loosely  connected  with  the  pericranium  by  the  connective 
tissue  which  intervenes,  thus  accounting  for  the  movement  of  the  integument 
when  the  occipito-frontalis  muscle  is  in  action. 

Action. — Contraction  of  the  anterior  belly  of  the  muscle  elevates  the  eye- 


61f)  SURGICAL  ANATOMY. 

brow  and  produces  wi'inkliug  of  the  forehead  ;  if  contraction  be  continued,  it  draws 
the  scalp  forward,  and  pulls  up  the  skin  of  the  nose,  to  the  extent  even  of  moving 
the  naso-labial  folds  ;  contraction  of  the  occipital  belly  draws  the  scalp  backward  ; 
and  alternate  contraction  of  the  two  bellies  moves  the  scalp  backward  and  forward. 

Dissection. — Divide  the  aponeurosis  in  the  median  line,  and  make  another 
incision  at  its  junction  with  the  frontalis  muscle.  Reflect  the  aponeurosis  outward 
and  backward,  and  the  frontalis  muscle  downward. 

Areolar  tissue  layer.— The  mobility  of  the  scalp  depends  entirely  upon  the 
laxity  of  the  subjacent  areolar  tis.sue  layer ;  it  is  this  layer  which  permits  ex- 
tensive flaps  of  the  scalp  to  be  torn  loose.  When  the  hairs  become  caught  in 
moving  machinery  the  entire  scalp  maj^  be  torn  off,  laying  this  tissue  bare. 
It  was  due  to  the  laxity  of  this  layer  that  the  American  Indian,  with  no  knowl- 
edge of  anatomy  or  surgery,  was  able  to  peel  off  the  scalp  with  so  much  ease. 
Exposure  of  the  skull  in  a  postmortem  examination  is  effected  by  peeling  off  the 
scalp  along  this  layer  of  tissue,  and  it  is  remarkable  with  what  ease  the  skull  can 
thus  be  exposed.  To  further  illustrate  the  laxity  of  this  tissue,  it  will  suffice  to 
relate  a  case  mentioned  by  the  late  D.  Hayes  Agnew :  A  midwife  attending  a 
woman  in  child-birth  incised  the  child's  scalp,  thinking  it  the  protruding  bag  of 
waters.  Labor  pains  came  on,  and  the  head  protruded  through  the  scalp  wound 
with  the  entire  vault  of  the  skull  laid  bare. 

Tumors. — By  careful  examination  tumors  situated  above  the  occipito-frontalis 
aponeurosis  or  in  it  will  be  seen  to  be  freely  movable.  All  immovable  growths  of 
the  scalp  should  be  most  carefully  examined  before  extirpation,  for  they  are 
probably  beneath  the  aponeurosis  ;  a  tumor  originating  within  the  cranium  may 
force  its  way  outward  and  form  a  prominence  on  the  scalp. 

Wounds  involving  only  the  skin  and  superficial  fascia  of  the  scalp,  when  the 
occipito-frontalis  muscle  or  its  aponeurosis  has  not  been  divided,  do  not  gape, 
because  of  the  close  adherence  of  the  skin  to  the  superficial  fascia  and  of  the 
superficial  fascia  to  the  aponeurosis.  The  areolar  tissue  layer  permits  of  wide 
separation  of  the  edges  of  a  wound  which  divides  the  occipito-frontalis  aponeu- 
rosis. Antero-posterior  wounds  which  involve  the  aponeurosis  gape  but  little, 
while  the  edges  of  transverse  wounds  are  widely  separated  by  the  contraction  of 
the  occipito-fi'ontalis  muscle.  The  great  vascularity  of  the  scalp  lessens  the  likeli- 
hood of  sloughing  and  gangrene.  A  large  flap  of  the  scalp  attached  by  but  a 
small  pedicle  is  much  less  likely  to  perish  than  a  flap  of  skin  torn  from  another 
part  of  the  body,  as  the  vessels  of  the  scalp  run  immediately  beneath  the  skin 
and  are  included  in  the  flap.  In  phlegmonous  erysipelas  and  in  deep  inflam- 
mation of  the  scalp  the  ari'olar  tissue  layer  becomes  infiltrated  with  jnis  and  conse- 
quently sloughs.     As  the  vessels  are  superficial  to  this  layer  the  skin  does  not 


SCI  LP.  617 

necrose,  ulcerate,  and  allow  pointing,  and  for  this  reason  it  is  important  to  incise 
early. 

The  pericranium  (external  periosteum)  is  l)Ut  loo.sely  attached  to  tliu  hune, 
except  at  the  sutures,  where  the  union  is  lirm.  In  lacerated  wounds  of  the  scalp 
the  pericranium  is  frequently  stripped  from  the  skull  to  the  (.'xtent  of  exposing 
large  areas  of  bone.  The  pericranium  differs  in  its  iunctions  from  the  peiiusteum 
covering  other  bones  in  that,  if  the  periosteum  be  removed  to  any  extent  hom 
another  bone,  the  part  of  the  bone  from  which  it  is  removed  will  most  probably 
necrose,  while  the  pericranium  may  be  stripped  from  a  considerable  part  of  the 
vault  of  the  cranium  without  necrosis  following.  This  is  due  to  the  fact  tha1>  the 
bones  of  the  skull  receive  their  blood  supply  chiefly  from  the  vessels  of  the  exter- 
nal (endosteal)  layer  of  the  dura  mater,  while  the  other  bones  are  nourished  to  a 
great  extent  through  their  periosteal  covering.  The  pericranium  at  the  sutures 
becomes  continuous  with  the  external  layer  of  the  dura  mater,  con.stituting  the 
so-called  intersutural  membrane.  It  is  also  continuous  with  the  dura  at  the  for- 
amina ;  hence  it  is  that  inflammation  of  the  pericranium  may  extend  by  continuity 
and  involve  the  dura  mater,  producing  pachymeningitis. 

Collections  of  blood  or  pus  in  the  scalp  may  be  situated  superficial  to  the 
occipito-frontalis  aponeurosis,  between  the  aponeurosis  and  the  pericranium  or 
beneath  the  pericranium.  A  collection  superficial  to  the  aponeurosis  is  of  but 
little  moment,  since  the  density  of  the  superficial  fascia  causes  it  to  be  circum- 
scrilied.  Collections  in  ■  the  areolar  tissue  layer,  between  the  aponeurosis  and  the 
pericranium,  are  limited  only  by  the  attachments  of  the  occipito-frontalis  nuisi'lu 
and  its  aponeurosis  ;  thus  they  may  undermine  the  entire  scalp  and  prove  serious 
if  not  evacuated  early.  Collections  beneath  the  pericranium  are  limited  to  a 
single  bone,  on  account  of  the  sutural  attachments  of  the  membrane.  Collections 
in  the  areolar  tissue  layer  call  for  drainage,  and  should  they  be  slow  in  healing, 
the  scalp  mu.st  be  firmly  bandaged  in  order  to  arrest  the  movements  of  the  occipito- 
frontalis  muscle.  Hematomata  in  the  areolar  tissue  layer  are  uncommon,  except 
as  a  result  of  fissured  fracture  of  the  skull  with  rupture  of  one  of  the  branches  of 
the  middle  meningeal  artery,  or  of  the  superior  longitudinal  or  lateral  sinus,  as 
the  areolar  tissue  between  the  aponeurosis  and  the  pericranium  contains  but  very 
few  vessels.  Collections  of  blood  beneath  the  pericranium,  generally  termed 
cephalhematomata,  must  be  limited  to  one  bone,  since  the  membrane  dips  into 
the  sutures  and  becomes  continuous  with  the  dura  mater ;  they  are  usually 
congenital  and  due  to  pressure  upon  the  head  at  birth. 

In  septic  inflammation  of  the  scalp  infection  may  reach  the  superior 
longitudinal  sinus  through  the  parietal  emi.?sary  vein  and  the  lateral  sinus 
through  the  occipital  and  posterior  auricular  veins  and  their  comnu;nications  with 

S-40 


618  SURGICAL  ANATOMY. 

the  mastoid  vein  which  empties  into  the  lateral  sinus.  Through  the  anastomoses 
between  the  diploic  veins  and  the  veins  of  the  pericranium  septic  material  in  the 
scalp  may  reacli  the  sinus  alse  parvte  and  the  cavernous  sinus  through  the  fronto- 
sphenoid  diploic  vein,  the  superior  petrosal  sinus  through  the  anterior  temporal 
diploic  vein,  and  the  lateral  sinus  through  the  posterior  temporal  and  occipital 
diploic  veins.  In  erysipelas,  abscess,  and  other  infectious  inflammations  of  the 
scalp  germs  may  enter  the  sinuses  through  these  various  routes  and  cause  throm- 
bosis, embolism,  and  pyemia. 

Temporal  fascia. — The  temporal  fascia  is  a  white,  shining  membrane,  which 
is  stronger  than  the  occipito-frontalis  aponeurosis  in  this  location,  and  which  gives 
attachment  by  its  under  surface  to  the  superficial  fibers  of  the  temporal  muscle. 
Above,  it  is  attached  to  the  entire  extent  of  the  temporal  ridge  as  a  single  layer ; 
while  below,  it  divides  into  two  laj^ers,  the  outer  of  which  is  attached  to  the 
external  and  the  inner  to  the  internal  border  of  the  upper  margin  of  the  zygo- 
matic arch  and  zygomatic  process  of  the  malar  bone.  Between  these  two  layers 
are  seen  a  small  quantity  of  fat,  the  orbital  branch  of  the  middle  temporal  artery, 
and  the  temporal  branch  of  the  temporo-raalar  or  orbital  branch  of  the  superior 
maxillary  nerve.  In  relation  with  its  outer  surface  is  the  extension  of  the  occipito- 
frontalis  aponeurosis,  the  orbicularis  palpebrarum,  the  attolens  and  attrahens 
aurem  muscles,  the  temporal  vessels,  the  auriculo-temporal  nerve,  and  the  temporal 
branches  of  the  orbital  and  facial  nerves.  Immediately  above  the  zygoma  it  is 
pierced  by  the  middle  temjjoral  artery,  a  branch  of  the  temporal. 

Density  of  the  temporal  fascia. — Owing  to  the  density  of  this  fascia  abscesses 
beneath  it  very  rarely  point  upon  the  surface,  the  pus  passing  in  the  direction  of  least 
resistance — namely,  through  the  pterygo-maxillary  region  into  the  mouth  or  neck. 
Its  unyielding  nature  is  well  illustrated  by  a  case  recorded  by  Denonvilliers :  "  A 
woman  who  had  fallen  in  the  street  Avas  admitted  to  the  hospital  with  a  deep 
wound  in  the  temporal  region  ;  a  piece  of  bone  several  lines  in  length  was  found 
loose  at  the  bottom  of  the  wound  and  was  removed.  After  its  removal  the  finger 
could  be  passed  through  an  opening  with  an  unyielding  border,  and  came  in 
contact  with  some  soft  substance  beyond.  The  case  was  considered  one  of  com- 
pound fracture  of  the  squamous  portion  of  the  temporal  bone,  with  separation 
of  a  fragment  and  exposure  of  the  brain.  A  bystander,  however,  noticed  that  the 
bone  removed  was  dry  and  white.  A  more  thorough  examination  of  the  wound 
revealed  the  fact  that  the  skull  was  uninjured,  that  the  suppo.sed  hole  in  the  skull 
was  merely  a  laceration  of  the  temporal  fascia,  that  the  soft  matter  beyond  was 
muscle  and  not  brain,  and  that  the  fragment  removed  was  simply  a  piece  of  bone, 
which,  lying  on  the  ground,  had  been  driven  into  the  soft  parts  when  the  woman 
fell  "  (Treves). 


PLATE  GLIII. 


Supraorbital  a 
Supraorbital  n 


Infraorbital  br.of  facial  n. 
Temporal  br.  of  orbital  n. 
Malar  br.of  facial  n. 


Auriculo-temporal  n. 
Middle  temporal  a. 
Anterior  auricular  a. 


Superficial  temporal  v, 
Superficial  temporal  a. 
Facial  n. 

Posterior  auricular  a. 
nternal  maxillary  a. 
uccal  br.of  facial. n. 

-Inframaxillary  br.of  facial  n. 


y  br.of  facial  n. 
I  a. 


Labial  br.  of  infraorbital  n)  Nasal  br.  of  infraorbital  n. 


TEMPORAL  FASCIA  AND   NERVES  OF  FACE. 
620 


PLATE  CLIV, 


iTemporal  m. 


Superficial  temporal  a. 
Facial  n. 

^  Internal  maxillary  a. 

Temporo-maxillary  v. 

Masseter  m 
Platysma  myoides  m. 


TEMPORAL  MUSCLE, 
621 


PLATE  CLV, 


INCISIONS  FOR   DISSECTION  AND  LINES  FOR  VESSELS  AND   NERVES. 

623 


FACE.  G2.5 

Dissection. — Tlie  temporal  fascia  slinuld  now  be  detached  from  Che  zygomatic 
arch  and  reflected  upward,  whrn  (lie  greater  ])ortion  of  the  temporal  muscle  and 
a  quantity  of  fat  overlying  the  muscle  above  the  zygoma  will  be  exposed.  The 
tendon  of  insertion  of  the  muscle  -will  be  seen  in  dissecting  tiie  face. 

The  temporal  muscle,  broad,  flat,  and  triangular,  is  situated  on  the  side  of 
the  head,  and  occupies  the  temporal  fossa.  It  arises  from  the  under  surface  of  the 
temporal  fascia  and  from  the  whole  of  tlie  temporal  fossa,  whence  its  fibers  descend 
and  converge  to  a  tendon  which  {)asses  under  the  zygomatic  arch  to  be  inserted 
into  the  apex,  the  inner  surface,  and  the  fore  part  of  the  coronoid  jirocess  of  the 
lower  jaw  down  to  tlie  last  molar  tooth. 

Blood  Supply. — From  the  middle  and  deep  temporal  arteries. 

Nerve  Supply. — Derived  from  the  temporal  branches  of  the  inferior  maxillary 
nerve. 

Action. — The  action  of  the  temporal  muscle  is  to  elevate  the  lower  jaw  ;  its 
posterior  fibers  also  assist  iii  drawing  the  lower  jaw  backward  after  other  nmscles 
have  carried  it  forward. 


FACE. 

Dissection. — The  dissection  of  the  face  should  follow  that  of  the  scalp. 
The  head  should  be  placed  in  the  same  position  as  for  the  dissection  of  the 
scalp,  but  slightly  lower,  and  turned  so  that  the  side  of  the  face  to  be  dissected 
is  upward.  The  cheeks  and  nostrils  should  be  distended  with  cotton  or  oakum 
and  the  lips  sewed  together.  The  muscles  and  vessels  should  be  dissected  on 
one  side  of  the  face  and  the  nerves  on  the  other.  The  incisions  are  made  as 
follows :  The  first  incision  is  made  from  the  nasal  eminence  along  the  median  line 
of  the  nose,  around  the  aperture  of  the  nostril,  along  the  median  line  of  the  upper 
lip,  around  the  mouth  along  the  line  where  the  skin  joins  tlie  mucous  membrane 
to  the  median  line  of  the  lower  lij),  anil  thence  to  the  point  of  the  chin.  A  second 
incision  is  carried  along  the  lower  border  of  the  jaw  to  the  angle  of  the  jaw,  then 
upward  to  the  lobe  of  the  ear.  Reflect  the  skin  outward.  The  facial  muscles 
(muscles  of  expression)  are  inserted  partly  into  the  skin,  and  great  care  must  be 
taken  that  they  are  not  removed  with  the  skin. 

The  skin  of  the  face  is  remarkably  thin,  and  freely  supplied  with  vessels  and 
nerves.  On  account  of  the  free  blood  supply  it  is  a  common  site  of  nevi,  except 
over  the  chin,  where  it  is  peculiarly  dense  and  adherent  to  the  parts  beneath. 
The  skin  covering  the  eyelids  and  the  bridge  of  the  nose,  owing  to  the  presence 


626  SURGICAL  ANATOMY. 

of  a  layer  of  lax  cellular  tissue,  is  loosely  adherent  to  the  parts  beneath.  Over  the 
cartilages  of  the  nose  the  skin  is  so  intimately  adherent  to  the  tissues  beneath  that 
it  is  removed  with  difficulty.  It  is  very  freely  supplied  with  sebaceous  and  sudor- 
iferous glands,  and  hence  is  commonly  the  site  of  acne  and  eruptions  which 
especially  involve  the  sebaceous  follicles ;  it  is  also  the  site  of  sebaceous  tumors. 
Facial  abscesses  usually  point  quickly  and  seldom  attain  large  size. 

The  superficial  fascia — the  cellular  tissue  layer  of  the  face — contains  a  con- 
siderable amount  of  fat,  except  in  the  eyelids  and  over  the  bridge  of  the  nose.  The 
laxity  of  the  cellular  tissue  favors  the  spreading  of  infiltrations,  so  that  the  cheeks 
and  other  parts  of  the  face  may  become  greatly  swollen.  In  general  dropsy  the 
face  soon  becomes  puffy,  the  edema  first  appearing,  as  a  rule,  in  the  lax  areolar 
tissue  of  the  lower  eyelid.  The  soft  tissues  of  the  cheek  favor  the  spread  of 
destructive  processes.  In  cancrum  oris — a  form  of  gangrene  of  the  mouth  attack- 
ing the  young — the  whole  cheek  may  be  lost  in  a  few  days.  Great  contraction  is 
apt  to  follow  upon  loss  of  substance,  so  that  the  jaw  may  be  firmlj'  closed  in  some 
cases,  as  is  seen  after  recovery  from  deep  ulceration  (Treves).  The  mobility  of  the 
tissues  of  the  face  renders  this  region  favorable  for  the  performance  of  plastic 
operations,  and  their  vascularity  insures  a  j^rompt  and  perfect  union.  Notwith- 
standing the  fact  that  there  is  a  large  quantity  of  fat  in  the  subcutaneous  tissue, 
fatty  tumors  are  rarely  seen  in  this  region.  The  thickness  of  the  tissues  of  the 
cheeks  and  lips  favors  the  embedding  of  foreign  substances  in  these  parts.  Thus, 
a  tooth  which  has  been  knocked  out  has  remained  embedded  in  the  lip.  Henry 
Smith  reported  a  remarkable  case  in  which  he  removed  a  piece  of  tobacco-pipe 
three  inches  long  from  the  cheek,  where  it  had  remained  for  several  j'cars. 

Dissection. — The  superficial  fascia — underlying  which  are  the  muscles, 
vessels,  and  nerves — should  be  removed  in  the  same  manner  as  the  skin,  taking 
care  not  to  disturb  the  muscles.  As  the  superficial  fascia  is  not  easily  removed 
in  a  continuous  layer,  it  may  be  taken  away  in  sections,  the  dissection  being  made 
in  the  line  of  the  muscular  fil)ers ;  this  is  necessary,  too,  in  order  to  avoid  dividing 
the  blood-vessels  and  nerves  of  the  face.  Tlio  removal  of  the  fascia  in  this  manner 
exposes  the  muscles,  the  vessels,  and  the  nerves. 

The  Muscles  of  the  Face  (muscles  of  expression)  are  divided  into  three 
groups :  those  of  the  nose,  those  of  the  eyebrows  and  eyelids,  and  those  of  the 
mouth — ('.  e.,  nasal,  palpebral,  and  oral. 

The  Muscles  of  the  Nose  are  the  pyramidalis  nasi,  the  compressor  nasi,  the 
levator  labii  suporioris  alajque  nasi,  the  dilator  naris,  and  the  depressor  alse  nasi. 

The  pyramidalis  nasi  muscle  covers  the  nasal  bone,  and  is  continuous  above 
with  the  li'ontalis  muscle,  where  it  is  attached  to  the  deep  surface  of  the  inter- 
superciliary  integument.     It  arises  from  the   aponeurosis   over  the  cartilage  of 


PLATE  CLVI, 


Occipito-frontalis  aporeuros.s 
Attrahons  aurem  m, 

AttoHens  aurem  m. 

Retrahens  aurem  m. 


Occipitalis  m. 


/        Parotid  gland 
Deep  portion  of  nnasseter  m. 


Superficial  portion  of 
masseter  m. 

Buccinator  m. 


Platysma  myoides  m. 


Orbicularis  oris  m. 
Depressor  labii  inferionsm 
Levator  menti  m. 
Posterior  dilator   narium  m 
Compressor   narium  m. 
Anterior  dilator    narium  m. 
Compressor   narium  minor  m. 


Zygomaticus  major  m. 
^Zygomaticus  minor  m. 
Risorius  m. 
Levator  anguii  oris  m. 
Levator  labii  superioiis  m. 
Levator  labii  superioris  alaeque  nasi 
Depressor  anguii  oris  m. 


MUSCLES  OF  FACE  AND  SCALP. 
627 


FACE.  629 

the  nose,  where  it  joins  the  lower  edge  of  the  nasal  bone  and  the  compressor 
nasi  muscle. 

Nerve  Sitply. — From  the  iiifru-orbital  branch  of  the  temporo-facial  division 
of  the  facial  nerve. 

Action. — It  renders  the  skin  over  the  cartilages  tense,  and  that  over  the  root 
of  the  nose  lax,  thus  forming  the  transverse  crease  at  the  root  of  the  nose. 

Tiie  compressor  nasi  muscle  is  triangular  in  shape,  arises  bj'  its  apex  from 
the  canine  fossa  of  the  supi'rior  maxillary  bone,  and  ends  in  the  aponeurosis 
covering  the  cartilaginous  part  of  the  nose,  blending  with  the  corresponding  muscle 
of  the  opposite  side.  The  origin  of  this  muscle  is  concealed  by  the  levator  labii 
superioris  alajque  nasi  muscle. 

Nerve  Supply. — From  the  infra-orbital  branch  of  the  upper  division  of  the 
facial  nerve. 

Action. — It  throws  the  skin  at  the  side  of  the  nose  into  vertical  wrinkles,  aids 
in  the  elevation  of  the  upper  lip,  and  slighth'  compresses  the  cartilaginous  ridge 
of  the  nose. 

When  the  compressor  nasi  muscle  is  reflected  from  the  median  line  outward, 
the  suiierficial  branch  (naso-labial)  of  the  nasal  nerve,  which  becomes  subcutaneous 
between  the  nasal  Ijune  and  the  lateral  nasal  cartilage,  will  be  seen  running  down- 
ward to  the  tip  of  the  nose. 

The  levator  labii  superioris  alaeque  nasi  muscle,  placed  by  the  side  of  the 
nose  and  overlai>pingtlie  origin  of  the  compressor  nasi  muscle,  arises  from  the  upper 
part  of  the  nasal  process  of  the  superior  maxilla.  It  descends,  and  divides  into  two 
portions  :  the  inner  and  smaller  ])art  is  inserted  into  the  inner  side  of  the  ala  nasi, 
and  the  outer  into  the  upper  lip,  blending  with  the  orbicularis  oris  muscle.  It 
is  partially  overlapped  near  its  origin  by  the  orbicularis  palpebrarum  muscle. 

Nerve  Supply. — From  the  infra-orbital  branch  of  the  facial  nerve. 

Action. — It  raises  the  inner  half  of  the  upper  lip,  and  draws  outward  the 
wing  of  the  nose,  thus  dilating  the  anterior  naris. 

The  dilator  naris  muscle  consists  of  two  portions — an  anterior  and  a  posterior. 
The  anterior  portion  is  a  thin  fasciculus  which  passes  from  the  lower  edge  of  the 
cartilage  of  the  wing  of  the  nose  to  the  integument  over  the  ala ;  the  po.sterior 
portion  arises  from  the  margin  of  the  nasal  notch  of  the  superior  maxilla  and 
from  the  outer  surface  of  the  sesamoid  cartilages  of  the  nose,  and  is  inserted  into 
the  skin  over  the  back  and  lower  margin  of  the  ala  of  the  nose. 

Nerve  Supply. — From  the  infra-orbital  branch  of  the  facial  nerve. 

Action. — It  enlarges  the  anterior  naris  by  raising  and  everting  its  outer  edge, 
thus  counteracting  its  tendency  to  be  closed  by  atmospheric  pressure.  In  condi- 
tions occasioning  dyspnea — e.  g.,  laryngeal  or  tracheal  obstruction — the  action  of 


G30  SURGICAL   ANATOMY. 

those  muscles  can  plainly  be  seen,  and  constitutes  one  of  the  signs  which  indicate 
tracheotomy  or  intubation. 

The  depressor  alae  nasi  is  a  short,  flat  muscle  which  may  be  exposed  when  the 
upper  lip  is  everted  and  its  mucous  membrane  removed  from  the  side  of  the  labial 
frenum.  It  arises  from  tlie  incisive  fossa  of  the  superior  maxilla,  whence  its  fibers 
ascend  to  be  inserted  into  the  septum  nasi  and  the  posterior  lower  jiart  of  the  wing 
of  the  nose. 

Nerve  Supply. — From  the  buccal  branch  of  the  cervico-facial  division  of  the 
facial  nerve. 

Action. — It  draws  downward  and  inverts  the  edge  of  the  nasal  cartilages. 

The  Muscles  of  the  Eyelids  and  Eyebrows  are  the  orbicularis  palpebrarum, 
the  corrugator  supercilii,  the  levator  palpebrae  superioris,  and  the  tensor  tarsi. 

Tendo  oculi  (tendo  palpebrarum). — Before  examining  the  orbicularis  palpe- 
brarum the  tendo  oculi  (internal  tarsal  ligament)  is  to  be  noted.  It  is  a  short 
tendon,  about  one-sixth  of  an  inch  in  length  by  one-twelfth  of  an  inch  in  breadth, 
and  can  readily  be  felt  at  the  inner  angle  of  the  eye  after  drawing  the  eyelids 
outward.  It  is  attached  to  the  nasal  process  of  the  sujierior  maxilla  in  front  of 
the  lacrymal  groove,  passes  transversely  outward  in  front  of  the  lacrymal  sac,  and 
divides  into  two  portions,  separated  by  the  caruncula  lachrymalis  ;  the  upper  portion 
is  attached  to  the  inner  extremity  of  the  upper,  and  the  lower  to  the  inner  extrem- 
ity of  the  lower,  tarsal  cartilage.  As  the  tendon  crosses  the  lacrymal  sac  it  gives 
off  a  strong  aponeurotic  lamina,  which  covers  the  sac  and  is  attached  to  the  margin 
of  the  lacrymal  groove.  This  expansion  will  be  seen  on  reflecting  that  portion  of 
the  orbicularis  palpebrarum  muscle  which  covers  the  lacrymal  sac.  To  jiuncture 
the  lacrymal  sac  a  knife  is  inserted  below  the  tendo  oculi  in  a  direction  downward 
and  a  little  backward,  dividing  the  skin,  the  orbicularis  palpebrarum  muscle, 
and  the  flbrous  expansion  derived  from  the  tendo  oculi.  The  angular  artery  and 
vein  are  situated  on  the  inner  side  of  the  incision. 

Tlie  external  tarsal  ligament  extends,  undivided,  transversely  inward  from 
the  edge  of  the  frontal  })rocess  of  the  malar  bone  to  the  adjacent  outer  extremities 
of  the  two  tarsal  cartilages. 

The  orbicularis  palpebrarum  (orbicularis  oculi,  sphincter  oculi)  is  a  thin, 
broad  muscle  which  surrounds  the  margin  of  the  orbit  and  the  eyelids,  forming  a 
.sphincter  ;  it  is  continuous,  above,  with  the  fibers  of  the  frontalis  muscle.  It  arises 
from  the  internal  angular  process  of  the  frontal  bone,  the  nasal  process  of  the 
superior  maxilla,  the  tendo  oculi,  and  the  lower  margin  of  the  orbit.  From  this 
origin  the  fibers  are  directed  outward,  forming  a  series  of  oval  curves  which  cover 
the  eyelids,  surround  the  margin  of  the  orbit,  and  spread  over  the  forehead, 
temple,  and  cheek.     The  central  fibers,  occupying  the  eyelids  and  connected  inter- 


PLATE  CLVII, 


Pulley 


Tendon  of  superior  oblique  m 


Superior  rectus  m 


Corrugatorsupercilii  m. 

Puncta  lachrymalia 
Meibomian  gland 


Conjunctiva 


Orbital  fat 

Inferior  rectus  m 

Inferior  oblique  m 


Tensor  tarsi  m. 


TENSOR  TARSI  AND  CORRUGATOR  SUPERCILIl   MUSCLES. 
632 


FACE.  GoS 

nally  with  the  tendo  oculi  ami  externally  willi  tlie  external  tarsal  ligament  ami 
the  malar  bone,  constitute  the  palpebral  porfinn  of  tlie  nniscle.  Tlic  lihers  of  this 
portion,  which  are  in  immediate  relation  witli  the  eyelashes,  have  been  described 
as  the  ciliar}/  mui^cle ;  but  this,  however,  must  not  be  confounded  with  the  ciliary 
muscle  proper — the  muscle  of  visual  accommodation.  More  peripheral  fibers  con- 
stitute the  orbital  portion  of  the  muscle.  The  latter  arise  from  the  internal  anjjular 
process  of  the  frontal  bone  and  from  the  nasal  pi'ocess  of  the  superior  maxillary 
bone,  and  are  distributed  around  the  margin  of  the  orl)it.  They  are  continuous 
above  with  the  frontalis  and  corrugator  supercilii  muscles,  and  extend  outward 
upon  the  cheek  to  mingle  with  the  elevators  of  the  upper  lip  and  nose  and  with 
the  zygomaticus  minor  muscle. 

Nerve  Supply. — From  the  temporal  and  malar  branches  of  the  temporo-facial 
division  of  the  facial  nerve  ;  hence  in  paralysis  of  this  nerve  the  eyelids  on  the 
paralyzed  side  can  not  be  closed. 

Action. — The  orbicularis  palpebrarum  muscle  closes  the  eyelids  and  protects 
the  eye.  The  palpebral  portion  of  the  muscle  contracts  during  winking.  Con- 
traction of  the  orbital  portion  presses  the  eyeball  backward  into  the  orbit  and 
draws  the  soft  parts  covering  the  margin  of  the  orbit  around  the  eyeball,  thus 
protecting  it  from  injury.  While  tliis  cushion  of  tissue  may  be  severely  bruised, 
as  is  seen  in  a  "black"  eye,  the  eyeball  itself  is  rarely  injured.  As  the  outer 
portion  of  the  orbicularis  is  mingled  with  the  fibers  of  the  frontalis  muscle 
and  the  elevators  of  the  upper  lip  and  nose,  slight  depression  of  the  eyebrow 
and  elevation  of  the  upper  lip  and  of  the  wing  of  the  nose  follow  contraction 
of  this  portion.  Strong  contraction  of  the  entire  muscle  holds  the  eye  firmly  in 
the  orbit,  thus  protecting  it  against  the  severe  strain  in  violent  coughing,  sneezing, 
and  vomiting,  during  which  acts  the  muscle  usually  contracts  spasmodically. 
Contraction  of  the  palpebral  portion  of  the  muscle  following  that  of  the  orbicular 
portion  tends  to  draw  the  lids  slightlj'  inward,  thus  directing  the  tears  to  the  inner 
angle  of  the  fissure  between  the  eyelids,  near  which  are  situated  the  puncta  lachry- 
malia. 

The  tensor  tarsi  (Horner's  muscle)  is  a  small  muscle,  really  a  deep  portion  of 
the  orbicularis  palpebrarum,  situated  at  the  inner  angle  of  the  orbit  behind  the 
tendo  oculi.  To  expose  it  it  is  necessary  to  cut  perpendicularly  through  the  middle 
of  the  upper  and  lower  eyelids,  when  the  nasal  half  of  each  lid  should  Ije  reflected 
inward  and  the  mucous  membrane  removed.  The  muscle  will  tie  seen  to  arise  from 
the  ridge  on  the  lacrymal  bone.  It  passes  outward  behind  the  lacrymal  sac  and 
divides  into  two  portions  which  cover  the  posterior  aspect  of  the  canaliculi.  The 
two  portions  terminate  in  the  inner  ends  of  the  uppjer  and  lower  tarsal  cartilages 
near  the  puncta  lachrj'malia. 


634  SURGICAL  ANATOMY. 

Nerve  Supply. — From  the  infra-orbital  branch  of  the  temporo-facial  division 
of  the  facial  nerve. 

Action. — It  compresses  the  lacrymal  sac.  i, 

The  corrugator  supercilii  muscle  arises  from  the  inner  end  of  the  superciliary 
ridge  of  the  frontal  bone.  Its  fillers  are  directed  outward  and  a  little  upward  to 
the  under  surface  of  the  orljicularis  palpeljrarum  and  frontalis  muscles,  to  be 
inserted  into  the  former  over  the  middle  of  the  supra-orbital  arch. 

Nerve  Supply. — From  the  temporal  branch  of  the  temporo-facial  division  of 
the  facial  nerve. 

Action. — It  draws  the  ej^ebrow  downward  and  inward,  thus  making  the 
vertical  wrinkle  of  the  forehead  at  the  inner  extremity  of  the  eyebrow. 

Dissection. — The  nasal  half  of  the  orbicularis  palpebrarum  and  a  small  jtart 
of  the  frontalis  muscle  having  been  reflected  inward,  the  corrugator  supercilii  is 
exposed. 

The  levator  palpebrae  superioris  muscle. — By  reflecting  the  outer  as  well 
as  the  nasal  half  of  the  orbicularis  palpebrarum  muscle,  and  detaching  the  orbito- 
tarsal  ligament  from  the  superior  orbital  margin  and  reflecting  the  ligament 
downward,  tlie  insertion  of  the  levator  palpebrse  superioris  muscle  by  a  broad 
aponeurosis  into  the  upper  border  of  the  tarsal  cartilage  of  the  upper  eyelid 
can  be  seen. 

The  Muscles  of  the  Mouth  are  the  orbicularis  oris,  the  levator  labii  supe- 
rioris, the  levator  anguli  oris,  the  zygomaticus  major,  the  zygomaticus  minor,  the 
buccinator,  the  risorius,  the  depressor  labii  inferioris,  the  depressor  anguli  oris,  and 
the  levator  laliii  inferioris. 

The  risorius  muscle  (Santorini's  muscle),  a  part  of  the  platysma  myoides, 
consists  of  a  thin  bundle  of  fibers  which  arises  from  the  fascia  covering  the 
masseter  muscle  and  parotid  gland,  and  passes  horizontallj'  forward  to  the  angle 
of  the  mouth,  where  it  joins  the  fibers  of  the  orbicularis  oris  and  depressor  anguli 
oris  muscles ;  some  of  its  fibers  pass  to  the  skin  at  the  angle  of  the  mouth. 

Nerve  Supply. — From  the  buccal  brancli  of  the  lower  division  of  the  facial 
nerve,  which  enters  it  from  beneath. 

Action. — It  retracts  the  corner  of  the  mouth.  Its  contraction  during  certain 
conditions,  as  in  tetanus,  causes  the  "  risus  sardonicus"  of  the  old  authors. 

The  orbicularis  oris  muscle  (sphincter  oris),  nearly  an  inch  in  breadth,  sur- 
rounds the  mouth,  forming  a  sphincter;  at  its  periphery  it  unites  with  several 
muscles  which  act  upon  that  aperture.  It  consists  of  two  parts — an  inner,  central, 
or  labial  part,  and  an  outer,  peripheral,  or  facial  i)art ;  the  two  differing  in  appear- 
ance and  in  the  arrangement  of  fibers,  like  the  orbicularis  palpebrarum  muscle. 
Tlie  inner,  central,  or  labial  portion  consists  of  pale,  thin  fibers,  fine  in  texture, 


FACE.  635 

corresponds  in  position  witli  tlic  red  margin  of  the  lips,  and  has  no  bony  attach- 
ment, but  is  continuous  around  tlie  angles  of  the  mouth  from  oni-  lip  to  the  other. 
The  outer,  peripheral,  or  facial  part  is  thinner  and  wider  than  the  labial,  and  has  a 
bony  attaclinient  as  well  as  connection  with  the  adjacent  muscles.  In  the  upper  lip 
the  orbicularis  oris  muscle  is  attached  at  each  .side  of  the  middle  line  to  the  lower 
part  of  the  septum  nasi  by  naso-labial  slips,  and  to  the  alveolar  border  of  the 
upper  jaw  opposite  the  incisor  teeth  ;  in  tlir  lower  lij)  it  is  attached  to  the  alveolar 
border  of  the  lower  jaw  opposite  the  canine  teeth  by  a  single  fasciculus  (musculi 
incisivi).  The  cutaneous  surface  of  the  nuiscle  is  intimately  connected  with  the 
skin  of  the  lips  and  surrounding  parts.  The  intimacy  of  this  union  is  so  great  in 
some  instances  that  the  mouth  is  surrounded  bj'  radiating  wrinkles,  especially 
marked  in  the  upper  lips  of  women.  The  labial  integument  of  the  male  probably 
contains  fewer  \\rinkles  on  account  of  the  presence  of  large  hair-bulbs.  The  deep 
surface  of  the  orbicularis  oris  is  covered  by  mucous  membrane,  between  which  and 
the  muscle,  in  the  .submucous  ti.ssue,  are  the  coronary  arteries  and  the  labial  glands. 

Nerve  Supply. — From  the  buccal  and  supra-maxillary  branches  of  the 
cervico-facial  division  of  the  facial  nerve. 

Action. — "When  the  facial  and  labial  portions  act  conjointly,  they  press 
together  and  project  the  lips.  Tlie  labial  fibers  acting  alone  bring  the  lips  and 
the  angles  of  the  mouth  together  and  invert  the  lips.  The  facial  fibers  acting 
alone  press  the  lips  against  the  alveolar  borders  of  the  jaws,  and,  at  the  same  time, 
evert  the  lips.  The  orbicularis  oris  is  the  antagonist  of  all  those  muscles  which 
converge  to  the  lips  from  the  various  parts  of  the  face.  Hypertrophy  of  the 
orbicularis  oris  or,  rather,  an  increase  of  the  connective  tissue,  particularly  of  the 
portion  in  the  upper  lip,  to  the  extent  of  producing  a  considerable  deformity,  is 
sometimes  seen,  and  indicates  a  plastic  operation  involving  the  removal  of  a  trans- 
verse, wedge-shaped  section  from  the  lip. 

The  levator  labii  superioris  muscle  (levator  labii  proprius)  arises  from  the 
superior  maxilla  above  the  infra-orbital  foramen,  and  is  inserted  into  the  upper 
lip,  its  fibers  blending  with  the  orbicularis  oris  muscle.  At  its  origin  it  is  over- 
lapped b}'  the  orbicularis  palpebrarum,  and  covers  the  infra-orbital  vessels  and 
nerves.     It  is  a  landmark  in  exposing  the  infra-orbital  nerve. 

Nerve  Supply. — From  the  infra-orbital  branch  of  the  upper  division  of  the 
facial  nerve. 

Action. — It  raises  the  upper  lip,  at  the  same  time  making  prominent  the  skin 
below  the  eye. 

Dissection. — The  levator  labii  superioris  muscle  is  to  be  reflected  downward 
from  its  origin,  when  will  be  exposed  the  levator  anguli  oris,  the  infra-orbital 
plexus  of  nerves,  and  the  infra-orbital  vessels. 


636  SURGICAL  ANATOMY. 

Tlie  levator  anguli  oris  muscle  (musculus  caninus)  arises  from  the  canine 
fossa  of  the  superior  maxilla  below  the  infra-orbital  foramen,  and  is  inserted  into 
the  angle  of  the  mouth,  superficial  to  the  buccinator  muscle,  its  fibers  blending 
with  the  orbicularis  oris,  the  zygomatici,  and  tlie  depressor  anguli  oris  muscle. 

Nerve  Supply. — From  the  infra-orbital  branch  of  the  upper  division  of  the 
facial  nerve. 

Action. — It  raises  and  draws  inward  the  angle  of  the  mouth. 

The  depressor  labii  inferioris  muscle  (quadratus  menti)  arises  from  the 
oblique  line  of  the  lower  jaw  by  a  wide  origin,  extending  from  a  point  below 
the  foramen  mentale  nearly  to  the  symphysis.  Its  fibers  are  associated  with 
those  of  the  muscle  of  the  opposite  side,  ascend,  and  are  inserted  into  the  integu- 
ment of  the  lower  lip,  blending  with  the  orbicularis  oris.  Its  outer  border  is 
overlapped  by  the  depressor  anguli  oris  muscle. 

Nerve  Supply. — From  the  supra-maxillary  branch  of  the  cervico-facial  divi- 
sion of  the  facial  nerve. 

Action. — It  depresses  and  everts  the  lip. 

The  depressor  anguli  oris  muscle,  triangular  in  shape,  hence  also  called 
triangularis  oris,  arises  from  the  oblique  line  of  the  lower  jaw  external  to 
the  depressor  labii  inferioris  muscles.  Its  fibers  ascend,  to  be  inserted  into  the 
angle  of  the  mouth,  intermingling  with  the  zygomatici,  the  levator  anguli  oris, 
the  risorius,  and  the  orbicularis  oris  muscle.  Its  outer  border  overlaps  the 
anterior  jaart  of  the  buccinator  muscle. 

Nerve  Supply. — From  the  supra-maxillary  branch  of  the  cervico-facial  divi- 
sion of  the  facial  nerve. 

Action. — It  draws  the  angle  of  the  mouth  downward  and  outward,  producing 
an  expression  of  sorrow. 

The  levator  labii  inferioris,  or  levator  menti,  is  a  small  muscle  seen  by 
everting  the  lip  and  dissecting  off  the  mucous  membrane  on  each  side  of  the 
laljial  frenum.  It  arises  from  the  fossa  below  the  incisor  teeth,  near  the  .symj)hysis. 
Its  fibers  descend,  and  are  inserted  into  tlie  integument  of  the  chin. 

Nerve  Supply. — From  the  supra-maxillary  branch  of  the  cervico-facial  divi- 
sion of  the  facial  nerve. 

Action. — It  assists  in  raising  the  lower  lip,  at  the  same  time  wrinkling  the 
integument  of  the  chin  over  the  point  of  its  insertion. 

Tlic  zygomatic  muscles  jiass  olili(|U(ly  from  the  zygomatic  arch  to  the  upper 
liji  and  angle  of  the  mouth.  The  zygomaticus  major  arises  from  the  outer  part 
of  the  malar  l)one  in  front  of  the  suture,  between  it  and  the  zygoma  ;  its  fibers  pass 
(iliii(|uely  downward  and  inward,  to  be  inserted  into  the  angle  of  the  month, 
blending  with  the  fibers  of  the  orbicularis  and    depressor  anguli  oris   muscles. 


FACE.  637 

The  zygomaticus  minor  arises  from  the  (lutcr  jiart  of  llic  malar  l)Oiic,  anterior  to 
the  zygomaticus  major,  and  Ix'hiiid  the  suture  between  the  malar  bone  and  Ihe 
superior  maxilla  ;  its  tihers  pass  downward  and  inward,  to  be  inserted  into  the 
lower  border  of  the  levator  labii  superioris  muscle.     It  is  often  absent. 

Nervk  Supply. — From  the  infra-orbital  branch  of  the  temporo-facial  divi- 
sion of  the  facial  nerve. 

Action. — The  zygomaticus  major  draws  the  corner  of  the  month  upward  and 
backward  ;  the  zygomaticus  minor  assists  the  levator  laljii  superioris  nmscle  in 
raising  the  upper  lip. 

Bucco-pharyngeal  fascia. — Before  making  a  dissection  of  the  buccinator 
muscle,  the  thin  layer  of  fascia  which  covers  and  adheres  closely  to  its  surface 
should  be  studied  ;  it  is  attached  to  the  alveolar  borders  of  the  superior  and  infe- 
rior maxillary  bones,  and  posteriorly,  where  it  is  thickest,  is  continuous  with  the 
fascia  over  the  constrictors  of  the  pharynx.  It  is  called  by  Holden  the  "bucco- 
pharyngeal fascia,"  since  it  supj^orts  and  strengthens  the  walls  of  the  pharynx  and 
mouth.  The  density  of  the  buccal  fascia  offers  a  barrier  to  the  escape  of  pus  into 
the  mouth  or  pharynx  from  an  abscess  in  the  cheek. 

The  buccinator,  quadrangular  in  form,  is  a  thin,  flat  muscle  which  occupies 
the  interval  between  the  jaws  at  the  side  of  the  fiice.  It  arises  from  the  outer 
surface  of  the  alveolar  borders  opposite  the  middle  and  jjosterior  molar  teeth  of  the 
superior  and  inferior  maxilla?,  and  Ijehind  from  the  pterygo-maxillary  ligament. 
The  ptcrygo-maxillari/  ligament  is  a  fibrous  band  extending  from  the  apex  (hamular 
process)  of  the  internal  pterygoid  plate  of  the  pterygoid  process  to  the  posterior 
extremity  of  the  internal  oblique  line  (inylodiyoid  ridge)  of  the  lower  jaw  ;  it 
separates  the  buccinator  muscle  from  the  superior  constrictor  of  the  jiharynx. 
The  fibers  of  the  buccinator  pass  forward,  to  be  inserted  into  the  orbicularis  oris 
muscle  at  the  angle  of  the  mouth.  The  central  fibers  intersect  one  another,  M'hile 
the  upper  fibers  pa.ss  to  the  upper  lip  and  the  lower  fibers  to  the  lower  lip.  In 
relation  with  the  superficial  surface  of  the  buccinator  muscle  is  a  large  mass  of  fat 
(buccal  pad),  which  separates  it  from  tlie  ramus  of  the  lower  jaw,  the  masseter 
muscle,  a  small  portion  of  the  temporal  muscle,  and  the  muscles  converging  to  the 
angle  of  the  mouth.  Aljsorption  of  the  fat  overlying  the  muscle  is  followed  by 
sinking  of  the  cheek,  as  seen  in  per.sons  who  are  emaciated.  In  compression  of  the 
brain  the  flapping  of  the  cheeks  in  breatliing  is  the  result  of  paraly.sis  of  the  nerve 
supplying  the  buccinator,  while  the  stertorous  breathing  (snoring)  is  the  result  of 
paralysis  of  the  nerves  of  the  soft  palate.  Tlie  duct  of  the  parotid  gland  (Stenson's 
duct),  which  pierces  the  Imccinator  muscle  opposite  the  second  molar  tooth  of  the 
superior  maxilla,  crosses  the  upper  part  of  the  muscle  obliciuely,  at  about  a  finger's 
breadth  below  the  zygoma.     It  is  also  crossed  by  the  facial  artery  and  vein  and 


638  SURGICAL  ANATOMY. 

by  branches  of  the  facial  nerve.  Internally  it  is  lined  by  the  mucous  membrane 
of  the  mouth  ;  between  this  and  the  muscle  lie  a  number  of  racemose  glands 
called  the  buccal  glands.  A  few  of  these  glands  are  found  on  the  outer  surface  of 
the  muscle  and  are  called  molar  glands. 

Nerve  Supply. — From  the  facial  nerve.  The  long  buccal  nerve,  a  branch  of 
the  inferior  maxillary,  pierces  the  buccinator  muscle  on  its  way  to  supply  the 
mucous  membrane  of  the  mouth. 

Action. — The  two  buccinator  muscles  widen  the  aperture  of  the  mouth 
transversely  and  contract  and  compress  the  cheeks  so  that  during  mastication  the 
food  will  not  remain  between  the  cheeks  and  the  teeth.  AVhen  but  one  mu.scle 
acts,  the  angle  of  the  mouth  is  drawn  to  that  side,  and  the  cheek  is  -wrinkled ; 
when  Avhistling,  the  muscle  contracts  and  prevents  bulging  of  the  cheeks. 

It  is  hardly  ftiir  to  the  earnest  dissector  to  leave  this  subject  without  the 
consoling  reminder  that  the  most  expert  dissectors  can  not  bring  out  these  muscles 
in  the  cadaver  as  they  are  shown  in  the  anatomic  plates.  It  must  be  remembered 
that  some  of  the  facial  muscles  belong  to  the  panniculus  carnosus  group,  so  exten- 
sive in  animals  but  so  limited  in  man.  In  some  faces  the  mu.sculature  is  a  com- 
plex network  of  subcutaneous  fibers  running  in  all  directions.  In  a  muscular 
subject  a  large  number  of  distinct  fasciculi  are  seen  crossing  one  another,  and  more 
or  less  merged  with  the  constant  muscles  of  the  face.  This  difference  in  the 
amount  of  facial  musculature  undoubtedly  accounts  for  much  of  the  variation  in 
the  amount  of  facial  wrinkling  observed  in  different  persons.  It  is  safe  to  my  that 
a  dissection  of  the  muscles  of  the  face  with  their  boundaries  as  well  defined  as 
shown  in  pictures  does  more  credit  to  the  dissector's  skill  in  imitating  a  diagram 
than  to  any  painstaking  effort  to  exhibit  the  natural  state  of  the  parts. 

The  Facial  Artery,  a  branch  of  the  external  carotid,  enters  the  face  over  the 
body  of  the  lower  jaw,  at  the  anterior  inferior  angle  of  the  masseter  muscle,  where 
its  pulsation  may  readily  be  felt  and  it  maj'  be  compressed  against  the  bone. 
Thence  it  ascends  forward  across  the  cheek,  over  the  buccinator  muscle,  and  beneath 
the  platysma  myoides  muscle,  to  the  angle  of  the  mouth  ;  thence  to  the  side  of  the 
nose,  to  terminate  at  the  inner  canthus  of  the  eye  as  the  angular  artery.  Where 
the  artery  passes  over  the  lower  jaw  it  is  covered  by  the  platy.sma  myoides  muscle 
and  the  deep  fascia  ;  near  the  mouth  it  passes  beneath  tlie  zygomatici  major  and 
minor  and  the  risorius  muscle ;  and  along  the  side  of  the  no.se  it  is  usually  covered 
by  the  levatur  ]al)ii  superioris  aheque  nasi.  It  rests  successively  on  the  lower  jaw, 
the  buccinator,  and  the  levator  anguli  oris  muscle.  The  companion  ves.sel  of  the 
facial  arter}',  {\\q  facial  vein,  runs  in  an  almo.st  .straight  line  from  the  inner  canthus 
of  the  eye  to  the  anterior  inferior  angle  of  the  masseter  muscle,  being  in  contact 


PLATE  CLVlll, 


Supraorbital  a 
Frontal  a. 


Orbital  a. 

Anterior  temporal  a. 

Posterior  temporal  a. 


Angular  a. 


Facial  a. 
Inferior  labial  a. 

nferior  coronary  a. 
Superior  coronary  a. 


Occipital  a. 


Posterior  auricular  a. 


Superficial  temporal  a. 
Anterior  auricular  a. 
Middle  temporal  a. 
parotid  gland 
Transverse  facial  a. 
Stenson's  duct 


ARTERIES  OF  SCALP  AND  FACE, 
G40 


PLATE  CLIX, 


Malar  br.  of  facial  n.     Transverse  facial  a 


Orbital  a 
Temporal  br.  of  orbital  n. 


Supraorbital  n. 


Supraorbital  a. 
Supratrochlear  n. 

Frontal  a 
Angular  a. 


Temporal  br.of  facial  n. 

Anterior  temporal  a. 
Superficial  temporal  a.  Posterior  temporal  a. 

Auriculo-temporal  n. 
/       Superfical  temporal  \ 


Occipital  a. 


/  Great  occipital  n. 


Small  occipital  n. 


Posterior  auricular  a. 


Infratrochlear 
n. 

Artery  of  septum 
Lateral  nasal  a. 

Superior  coronary  a, 
Inferior  coronary  a 

Inferior  labial  a, 

Facial  a 

Facral 


Anterior  auricular  a. 
Middle  temporal  a. 
Parotid  gland 
Supramaxillary  br.  of  facial  n. 
Stenson's  duct 


Buccal  br.of  facial  n. 
Infraorbital  br.of  facial  n. 
Socia  parolidis 


ARTERIES,   NERVES,  AND  MUSCLES  OF  SCALP  AND  FACE. 
641 


FACE.  643 

with  the  facial  artery  at  tliesc  points,  luit  eiscwlicrc  above  and  external  to  it.  The 
artery  is  crossed  by  filaments  of  the  facial  nerve,  while  the  levator  laliii  superioris 
niiisele  separates  it  from  the  infra-orbital  nerve  behind. 

Branches  of  the  Facial  Portion  of  the  Facial  Artery. — These  are  the  mus- 
cular, inferior  labial,  inferior  coronary,  superior  coronary,  lateralis  nasi,  and  angular. 

The  muscular  branches  are  directed  outward  to  supply  the  buccinator, 
masseter,  and  internal  ptervi^oid  muscles.  They  anastomose  with  t!u!  masseteric 
and  buccal  branches  of  the  internal  maxillary  and  with  the  infra-orbital  and 
transverse  tixcial  arteries. 

The  inferior  labial  artery  passes  inward  beneath  the  depressor  anguli  oris  to 
supply  the  nuiscles  and  integument  of  the  lower  lip  and  chin.  It  anastomoses  with 
the  inferior  coronary,  the  submental  branch  of  the  facial,  and  the  mental  branch  of 
the  inferior  dental  artery. 

The  inferior  coronary  artery  arises,  either  independently  or  in  common  with 
the  inferior  labial,  from  the  facial  artery  near  the  angle  of  the  mouth.  It  passes 
forward  and  inward  in  a  tortuous  manner  beneath  the  depressor  anguli  oris  toward 
the  angle  of  the  mouth,  then  pierces  the  orbicularis  oris,  and  continues  between 
it  and  the  mucous  membrane  along  the  free  margin  of  the  lower  lip.  It  anas- 
tomoses with  the  inferior  coronary  artery  of  the  opposite  side,  the  inferior  labial, 
and  the  mental  branch  of  the  inferior  dental  artery. 

The  superior  coronary  artery,  which  is  larger  and  takes  a  more  tortuous 
course  than  the  inferior  coronary,  arises  from  the  facial  artery  beneath  the  7.ygo- 
maticus  major  muscle.  It  pierces  the  orbicularis  oris,  and  runs  between  it  and  the 
mucous  membrane  along  the  free  margin  of  the  upper  lip  to  anastomose  with  the 
artery  of  the  opposite  side.  By  the  anastomosis  of  the  superior  and  inferior 
coronary  arteries  with  their  fellows  an  arterial  circle  is  formed,  which  surrounds 
the  mouth  and  can  be  felt  pulsating  on  the  internal  surface  of  the  lips  between 
one-fourth  and  one-half  of  an  inch  from  the  junction  of  the  skin  and  the  mucous 
membrane.  A  small  branch  to  the  ala  nasi  and  numerous  branches  to  the  labial 
glands  are  given  off  from  this  circle. 

The  artery  of  the  septum  of  the  nose  is  a  liranch  of  the  superior  coronary. 
The  tAvigs  of  this  arteria  septum  narium  are  a  common  source  of  epistaxis  (nose- 
bleed). The  hemorrhage  from  the  branches  of  this  vessel  is  readily  controlled  by 
compression  of  the  artery  of  the  septum,  either  by  direct  backward  pressure  against 
the  upper  lip,  or  1)y  pressure  from  within  outward,  as  when  a  firm  pledget  of 
cotton,  paper,  or  other  substance  is  pushed  well  up  under  the  lip  so  as  to  put 
its  tissues  upon  the  stretch  and  occlude  the  lumen  of  the  artery.  This  is  a 
common  procedure  practised  by  the  laity.  Another  simple  method  is  that  of 
holding  the  cartilaginous  end  of  the  nose  between  the  thumb  and  finger. 


644  SURGICAL  ANATOMY. 

Harelip. — In  the  operation  for  liarelip  the  bleeding  can  be  controlled  by 
grasping  the  lip  between  the  thumb  and  forefinger.  In  introducing  the  harelip 
pin  or  suture,  it  must  be  passed  deep  enough  to  go  Ijeneath  the  divided  coronary 
arterj^.  Harelip  is  a  congenital  deformity  consisting  of  one  or  more  fissures  in  the 
upper  lip,  the  result  of  arrested  development.  It  may  l)e  single  or  double,  the 
fissure  or  fi.ssures  being  to  the  side  of  the  median  line  of  the  lip,  corresponding  to 
the  line  of  union  between  the  intermaxillary  and  the  superior  maxillary  bone.  In 
double  harelip  the  intermaxillary  bone  is  often  displaced  forward.  Double  harelip 
is  frequently  associated  with  cleft  palate. 

The  lateralis  nasi  artery  ari.ses  from  the  focial  artery  opposite  the  wing  of  the 
nose,  and  passes  forward  over  the  lower  part  of  tlie  nose  and  over  the  ala  ;  it 
supplies  the  side  and  dorsum  of  tlie  nose,  and  anastomoses  witli  the  lateralis  nasi 
artery  of  the  opposite  side,  the  nasal  brancli  of  the  ojdithalmie,  the  infra-orbital, 
and  the  artery  of  the  septum. 

The  angular  artery,  the  terminal  part  of  the  facial,  passes  to  the  inner 
canthus  of  the  eye,  where  it  lies  on  the  nasal  side  of  the  lacrymal  .sac  and  tendo 
oculi ;  it  anastomoses  with  the  nasal  branch  of  the  ophthalmic  and  with  the  infra- 
orbital artery,  and  supplies  branches  to  the  cheek.  In  opening  an  abscess  of  the 
lacrymal  sac  it  is  important  to  bear  in  mind  the  situation  of  this  arterj'  on  the 
inner  side  of  the  sac. 

Nervi  molles. — The  focial  artery  and  its  liranches  are  surrounded  l)y  a 
minute  plexus  of  sympathetic  fibers  (nervi  molles)  not  demonstrable  macroscopi- 
cally.  These  fibers  are  liranches  of  the  superior  cervical  ganglion  of  the  sympa- 
thetic, and  supply  the  walls  of  the  artery  and  its  l.)ranches ;  they  furnish  the 
sympathetic  root  to  the  sul)maxillary  ganglion. 

Transverse  facial  artery. — I'assing  transversely  acro.ss  the  face  between  the 
zygoma  and  the  duet  of  the  parotid  gland,  and  resting  upon  the  masseter  muscle, 
is  the  transverse  facial  artery,  which  arises  from  the  temporal  artery  in  the 
substance  of  the  parotid  gland.  It  sup]ilies  the  small,  often  detached,  part  of  the 
parotid  gland  (the  socia  parotidis)  in  relation  with  the  duct,  the  ma.s.seter  and 
orbicularis  palpebrarum  muscles,  and  the  integument.  It  anastomoses  with  the 
infra-orbital,  facial,  and  masseteric  arteries.  It  is  acc()m])anied  liy  tAvo  or  three 
liranches  of  the  facial  nerve.  It  is  (|uite  small  except  wlien  it  supplies  those  parts 
wiiich  usually  recei\-('  blood  from  tlie  facial  artery.  It  occasionally  gives  ot^' the 
coronary  and  nasal  arteries,  the  facial  itself  jjeing  small.  It  arises,  at  times,  from 
the  external  carcitid  artery. 

'i'lie  facial  vein,  tlie  eontinuatiim  nf  tlie  angular  vein,  and  formed  by  the  union 
of  the  frontal  and  supra-orbital  viins,  eunnuenees  at  the  inner  canthus  of  the  eye  and, 


PLATE  CLX, 


Supraorbital 
Frontal  veins 


Transverse  facial 
Orbital  V. 


Middio  tonnporal  v. 
/         Superficial  temporal  v. 


|Connmunication  with  mastoid  v. 
Occipital  V. 


Deep  cervical  v. 

lerior  division  of  temporo-maxilldry  v. 
nterior  division  of  temporo-maxillary  v. 
External  jugular  v. 
Posterior  jugular  v. 


VEINS  OF  SCALP,   FACE,  AND   NECK, 
645 


FACE.  647 

as  already  statcil,  runs  in  an  almost  strai<j;lit  lino  to  the  anterior  inferior  an^le  of 
the  masseter  musele,  where  it  comes  into  relation  witli  tlic  outer  side  of  the  facial 
artery.  In  its  course  across  the  face  it  lies  ahove  and  to  the  outer  side  of  the 
artery,  passing  over  the  levator  lahii  superioris,  beneath  the  zygomatic  muscles, 
and  over  the  parotid  duct,  the  buccinator  nuiscle,  the  anterior  inferior  angle  of  the 
masseter  nuisele  and  niassetei'ic  fascia,  and  the  l)ody  of  tiie  Iowht  jaw.  Below  the 
jaw  it  is  joined  by  the  anterior  branch  of  tlie  temporo-maxillary  vein,  and  enijities 
into  the  internal  jugular  vein.  It  receives  veins  from  the  lower  eyelid  (the  inferior 
palpebral),  from  the  side  of  the  nose  (the  lateral  nasal),  from  the  orbital  vein,  and, 
beneath  the  zygomaticus  major  muscle,  a  branch  (deep  facial)  from  tlie  ])terygoid 
plexus,  besides  muscular  branches  and  branches  corresponding  to  those  of  the 
facial  artery.  The  facial  vein — through  the  angular,  in  which  it  coniniences — 
communicates  freely  with  the  ophthalmic  vein,  and  thus  with  the  cavernous  sinus  ; 
and  it  also  communicates  with  the  cavernous  sinus,  through  the  deep  facial  vein 
with  the  pterygoid  plexus  of  veins,  which,  in  turn,  communicates  with  the  sinus 
by  means  of  small  veins  which  pass  through  the  foramen  ovale,  the  foramen  of 
Vesalius,  and  the  middle  lacerated  foramen.  Owing  to  the  free  communication 
between  the  vein  and  the  cavernous  sinus,  the  latter  is  endangered  by  any  intiam- 
matory  condition  of  the  facial  vein. 

Disease  involving  the  facial  vein. — The  facial  vein,  as  a  rule,  has  no 
valves;  it  Avill  therefore  be  understood  h»w  emboli  are  readily  carried  to  the 
internal  jugular  vein  and  thus  into  the  general  circulation.  Carbuncle  of  the  face 
may  i)rove  iiital  by  inducing  thrombosis  of  the  cerebral  sinuses  through  the  com- 
munications previously  described.  Any  deep  inflammation  of  the  face,  as  phleg- 
monous erysipelas,  may  be  complicated  by  thrombosis  or  pyemia.  The  injec- 
tion of  facial  nevi  in  infants  may  result  in  death  from  thrombosis,  owing  to  the 
direct  communication  of  the  facial  with  the  internal  jugular  vein.  Pulmonary 
embolism  and  death  have  followed  tlie  injection  of  perchlorid  of  iron  for  nevoid 
growths  of  the  face.  In  arterio-venous  aneurysm  of  the  cavernous  sinus  arterial 
blood,  through  the  ophthalmic  and  angular  veins,  flows  through  the  facial  vein 
and  gives  rise  to  a  pulsating  varicose  condition  of  the  latter  vein  and  a  distinct 
thrill  and  bruit. 

Vascularity  of  the  face. — It  has  been  demonstrated  that  the  tissues  of  the 
face  are  very  vascular.  In  persons  exposed  to  cold,  or  in  those  addicted  to  strong 
drink,  the  very  small  vessels  of  the  skin,  especially  over  the  nose,  appear  per- 
manently injected  or  varicose.  Attention  has  been  called  to  the  fact  that  nevi 
and  various  forms  of  erectile  tumors  are  common  about  the  face.  Wounds  of 
the  face,  while  they  bleed  freely,  heal  very  rapidly;  their  edges  should  be 
carefully  adjusted  as  soon  after  the  accident  as  possible.      "  Extensive  flaps  of 


648  SURGICAL  ANATOMY. 

skin  which  have  been  torn  up  in  lacerated  wounds  of  the  face  often  retain  their 
vitality  in  almost  as  marked  a  manner  as  similar  flajis  torn  from  the  scalp " 
(Treves).  The  anastomoses  of  the  facial  artery  are  so  free  that  when  the  vessel  is 
divided,  both  ends  bleed  freely  and,  according  to  the  general  rule,  they  sliould 
both  be  tied. 

Dissection. — Upon  the  side  of  the  face  on  which  the  muscles  have  been 
exposed  the  appendages  of  the  eye, — including  the  eyelids,  eyebrows,  eyelashes, 
tarsal  cartilages,  conjunctiva,  and  lacrymal  caruncle, — tlie  parotid  gland,  and  the 
external  ear  should  be  carefully  dissected  before  turning  the  head  to  make  the 
dissection  of  the  nerves. 

The  eyebrow  is  a  prominent  arch  of  integument  connected  with  the  orbicu- 
laris palpebrarum,  corrugator  supercilii,  and  occipito-frontalis  muscles.  It  is 
covered  by  numerous  short,  thick  hairs  which  surmount  the  upper  circumference 
of  the  orbit,  their  general  direction  being  outward,  though  they  interlace,  the 
upper  ones  curving  downward  and  the  lower  ones  upward.  They  serve  the  two- 
fold purpose  of  acting  as  a  shield  against  the  admission  of  foreign  bodies  to  the 
eye,  and  as  a  multiple  spring  buffer  reducing  somewhat  the  impact  of  blows  against 
the  brow,  thus  often  preventing  serious  wounds  of  the  skin  from  traumatism 
applied  against  the  sharp  supra-orbital  margin. 

The  eyelids  (palpebrte)  are  two  movable  semilunar  curtains  placed  in  front 
of  each  eyeball  to  protect  that  exceedinglj'  delicate  and  important  organ.  Their 
free  edges  are  transverse  and  are  studded  with  hairs,  called  eyelashes.  The  upper 
lid  is  the  longer,  so  that  when  the  lids  are  closed,  their  margin  of  contact  lies  below 
the  center  of  the  eye.  The  upper  lid  is  also  more  freely  movable  ;  it  has  a  special 
muscle  to  raise  it — the  levator  palpebrte  superioris.  The  interval  between  the 
open  eyelids  is  called  the  fissura  palpebrarum,  or  interpalpebral  slit.  At  the 
points  of  union  of  the  eyelids  are  the  external  and  internal  cantlii,  or  palpebral  com- 
missures. The  internal  canthus  is  the  larger ;  within  it  is  a  triangular  space 
containing  a  depression,  the  lacus  lachrymalis,  and  an  elevation,  the  caruncula 
lachrymaUs.  At  their  free  margins,  which  are  concave,  the  lids  are  thickest. 
At  their  inner  extremities  and  upon  their  free  surfaces  are  two  small  eleva- 
tions— the  papillse  lachrymaliie,  in  the  center  of  which  are  small  openings  called 
the  punda  lachryvKilia,  the  orifices  of  the  laerywal  canalicuH.  The  free  margins 
are  provided  in  front  with  eyelashes  and  witli  orifices  of  sebaceous  and  modified 
sweat  glands ;  and,  behind,  with  small  opening.s — the  orifices  of  the  ducts  of  the 
Meibomian  glands.  That  portion  of  the  lids  internal  to  the.  orifices  of  the 
lacrymal  canaliculi  is  devoid  of  eyelashes  and  IMeibomian  glands,  ^^'hen  the  ej'e- 
lids  are  closed,  an  interval  exists  between  the  lids  and  the  ej'eball  for  the 
inward  passage  of  the    tears.     Inflannuatiou  of  the    ducts   opening  on    the  free 


PLATE  CLXI. 


Lacrymal  punctum 
Lacrymal  caruncle, 


Lacrymal  punctum 

Plica  semilunaris 


Orifices  of  ducts  ot 
meibomian  glands 


S— 43 


PALPEBRAL  FISSURE  AND  EYEBALL-EYELIDS  EVERTED. 
G19 


FACE.  651 

mar<:;iii  of  the  eyelid,  wliicli  usually  allects  those  on  the  anterior  border,  con- 
stitutes a  stye. 

The  eyelashes  (cilia)  are  two  or  more  rows  of  short,  thick,  curved  hairs,  fixed 
in  the  anterior  margin  of  the  free  border  of  the  eyelids.  They  are  longer  and 
more  numerous  in  the  ujipcr  lid,  and  have  their  convexities  directed  downward, 
while  those  of  the  lower  lid  have  their  convexities  directed  upward.  They  protect 
the  eye  against  the  admission  of  dust  and  other  foreign  substances,  especially 
during  high  winds. 

The  conjunctiva. — Before  dissecting  the  eyelid,  the  conjunctiva  and  the  lac- 
rymal  caruncle  should  be  examined.  The  conjunctiva  is  the  mucous  membrane 
which  covers  the  inner  surface  of  the  eyelids  and  the  anterior  part  of  the  eyeball. 
At  the  free  margin  of  the  lids  it  is  continuous  with  the  integument.  The  part 
covering  the  eyeball  is  in  relation  with  the  selei'otic  and  the  cornea.  The  conjunc- 
tiva consists  of  four  divisions:  the  palpebral,  the  portion  in  relation  with  the  eye- 
lids ;  the  reflected,  the-  jiortion  lietween  the  eyelids  and  the  eyeliall  ;  the  sclerotic, 
and  the  corneal  portions.  The  lacrymal  ducts  (exci-etory  ducts  of  the  lacrymal 
gland)  empty  upon  the  free  surface  of  the  reflected  portion  of  the  conjunctiva. 
The  palpebral  portion  is  more  vascular  than  the  remaining  parts,  and  is  studded 
with  a  number  of  small  papilhe,  wliicli,  when  enlarged  by  inflammation,  con- 
stitute the  disease  known  as  granular  lids,  though  this  condition  is  at  times  also 
due  to  true  granulations,  whicli  have  a  similar  origin.  The  conjunctiva  covering 
the  sclerotic  is  loosely  attached,  and  that  covering  the  cornea  is  very  thin,  consisting 
merely  of  an  epithelial  layer  which  is  very  adherent.  In  congestion  of  the  con- 
junctiva with  effusion  into  the  loose  subconjunctival  tissue  (chemosis)  the  mem- 
brane is  at  times  SAVollen  to  the  very  edge  of  the  cornea,  where  it  then  forms  a 
sharp  elevated  margin. 

The  caruncula  lachrymalis  is  a  small,  reddish  elevation  situated  at  the  inner 
canthus  in  the  lacus  lachrymalis.  It  consists  of  a  separated  portion  of  skin,  which 
presents  minute  hairs  upon  its  surface.  It  contains  connective  tissue,  a  small 
number  of  plain  and  striated  muscular  fibers  and  modified  sweat  glands,  as  well 
as  a  few  sebaceous  glands.  External  to  the  caruncle,  and  resting  upon  the  eyeball, 
is  a  vertical  triangular  folil  of  conjunctiva,  with  its  free  concave  margin  directed 
toward  the  cornea  ;  this  is  called  the  plica  semilunaris,  and  is  a  rudimentary  mem- 
brana  nictitans  (the  third  eyelid  in  birds).  Miiller  found  smooth  muscular  fibers 
in  this  fold,  and  in  some  of  the  domestic  animals  a  thin  plate  of  cartilage  has  been 
discovered  in  it  (Gray). 

As  previously  stated,  the  conjunctiva  is  contiimous  with  the  skin  at  the  free 
borders  of  the  lids.  It  is  also  continuous,  through  the  lacrymal  canaliculi, 
with  the  mucous   membrane  lining   the    lacrymal    sac,  the  nasal  duct,    and  the 


652  SURGICAL  ANAT03IY. 

inferior  meatus  of  the  nose.  In  the  loose  sul)Conjunctival  tissue  there  are  not  infre- 
quently seen,  esjiecially  in  elderly  persons,  small  yellowish  masses  of  fut,  called 
Pingueculae. 

In  post-conjunctival  operations,  as  in  section  of  the  ocular  muscles,  the  con- 
junctiva must  be  cut.  Its  lax  attachment  to  the  sclera  is  now  of  advantage, 
for  a  loose  fold  is  readily  raised  with  the  forceps  and  incised  to  the  required  extent, 
after  -which  it  is  with  ample  facility  peeled  back  as  far  as  necessary. 

The  eyelids  are  composed  of  the  skin,  subcutaneous  tissue,  orbicularis  palpe- 
brarum muscle,  palpebral  ligaments,  orbito-tarsal  ligaments,  the  tarsal  cartilages, 
Meibomian  glands,  vessels,  and  nerves,  and  conjunctiva.  The  upper  lid  contains, 
in  addition  to  the  structures  just  mentioned,  the  aponeurotic  insertion  of  the  leva- 
tor palpebrfe  superioris  muscle.  The  skin  of  the  lids  and  the  orbicularis  palpe- 
brarum muscle  have  already  been  described. 

The  subcutaneous  areolar  tissue  of  the  eyelids  contains  no  ht.  Its  laxity 
accounts  for  the  extensive  ecchymosis  after  comparatively  slight  traumatism,  and 
for  the  early  appearance  of  puffiness  of  the  eyelids  in  chronic  Bright's  disease. 

The  palpebral  ligaments  are  fibrous  bands  attaching  the  tarsal  cartilages  to 
the  outer  and  inner  margins  of  the  orbit.  The  external  ligament  is  undivided 
and  extends  from  the  malar  bone  to  the  outer  extremities  of  the  tarsal  cartilages. 
The  internal  ligament  (tendo  oculi)  extends  from  the  nasal  process  of  the  superior 
maxilla  and  the  crest  of  the  lacrymal  bone  to  the  internal  extremities  of  the  tarsal 
cartilages.  The  division  of  the  tendo  oculi  which  is  attached  to  the  nasal  process 
of  the  superior  maxilla  passes  in  front  of  the  lacrymal  sac,  while  the  limb  attached 
to  the  crest  of  the  lacrymal  bone  passes  over  its  outer  wall. 

The  orbito-tarsal  ligaments  (palj^ebral  fasciae)  are  fibrous  membranes  continu- 
ous with  the  periosteum,  and  extend  from  the  .superior  and  inferior  orliital  mar- 
gins to  the  tarsal  cartilages.  In  the  upper  lid  the  orbito-tarsal  ligament  fuses  with 
the  tendon  of  the  levator  palpebrte  superioris  muscle.  These  ligaments  prevent 
pus  in  the  subcutaneous  areolar  tissue  from  making  its  way  into  the  orbit,  and 
hence  are  called  the  septa  orbitale. 

Tiic  tarsal  cartilages,  situated  in  the  free  margins  of  the  eyelids,  are  two 
plates  of  dense  connective  tissue.  They  are  thickest  at  their  free,  or  ciliary, 
margins,  and  give  support  and  shape  to  the  eyelids.  The  cartilage  of  the 
upper  lid  is  much  larger  than  that  of  the  lower,  and  gives  attachment  to  the 
aponeuro.sis  of  the  levator  palpebrse  superioris  muscle.  In  both  lids  the  attached 
margins  of  the  tarsal  cartilages  are  continuous  with  the  orbito-tarsal  ligaments. 

Tlic  Meibomian  glands  are  sebaceous  glands  lodged  in  the  substance  of  the 
tarsal  cartilages,  and  number  between  twenty  and  thirty  in  the  upper  and  some- 
what less  in  the  lower  lid.     The  orifices  of  the  glands  open  on  the  free  borders  of 


PLATE  CLXII, 


Superior  portion  of  lacrymal  gland 

Inferior  portion  of  lacrynnal  gland 

Levator  palpebrae  superioris  m. 


Frontal  sinus 


Meibomian  glands 
Conjunctiva 
Orifices  of  ducts  of  meibonnian  glands 
Orifices  of  lacrymal  ducts 


Tensor  tarsi  m. 
Lacrymal  sac 


Lacrymal  canaliculi 


LACRYMAL  APPARATUS  AND  MEIBOMIAN   GLANDS. 
653 


FACE.  655 

the  lids  behind  the  lashes.  Each  ul^nid  consi.st,s  of  a  straight  tube  with  many 
slioil  lilind,  diverticula.  The  Meibuniiiin  glands  secrete  a  sebaceous  material 
which  in-rvrnls  the  lids  from  adhering,  and  arc  readily  distinguished  as  closely 
ad.ja.viit,  vertical,  parallel,  yellow  streaks  across  the  inner  surface  of  the  lids. 
W  in  11  the  duct  of  one  of  these  glands  becomes  occluded,  a  retention  cyst,  similar 
to  a  wen,  is  formed. 

Non-striated  muscular  fibers  are  found  in  lioth  lids.  In  the  upper  lid  these 
fibers  originate  from  the  lower  surface  of  the  levator  jjalpebraj  superioris ;  in  the 
lower  lid  they  arise  from  the  vicinity  of  the  inferior  oblique  muscle.  In  lioth 
lids  they  are  inserted  close  to  the  attached  border  of  the  tarsal  cartilage.  They 
are  known  as  the  superior  and  inferior  i>alpebral  muscles  of  Miiller. 

Blood  Supply.— The  eyelids  receive  their  blood  supj.ly  from  the  palpebral 
and  lacrymal  branches  of  the  ophthalmic  artery  and  from  small  branches  of  the 
temporal  and  transverse  facial  arteries.  The  palpebral  branches  of  the  ophthalmic, 
two  in  number,  arise  from  tliat  artery  near  the  pulley  of  the  superior  oblique 
muscle  ;  one  is  found  in  each  lid  and  runs  through  the  fibrous  tissue  layer  of  the 
lids  between  the  orbicularis  palpebrarum  mu.scle  and  the  tar.sal  cartilages  near 
their  margins.  The  lacrymal  is  the  first  branch  of  the  ophthalmic  artery.  It 
accompanies  the  lacrymal  nerve  and  gives  off  palpebral  twigs  which  anastomose 
with  the  other  palpebral  arteries  to  form  the  tarsal  arches. 

The  veins  of  the  eyelids  are  larger  than  the  arteries,  and  outnumber  them. 
They  empty  into  the  frontal  and  angular  A^eins  at  the  inner  canthus,  and  into  the 
orbital  vein  at  the  outer  canthus.  Some  of  the  veins  of  the  lids  pass  between  and 
through  tlie  l)undles  of  fibers  of  the  orbicularis  palpebrarum,  and  hence  in  many 
inflammatory  conditions  of  the  conjunctiva  and  cornea  in  children,  in  wliich 
prolonged  spasm  of  this  muscle  occurs,  the  lids  arc  very  apt  to  become  edematous, 
from  interference  with  the  venous  flow  (Fucho). 

Nerve  Supply.— The  nerve  supply  is  free.  The  nerves  to  the  palpebral 
portion  of  tlie  orbicularis  palpebrarum  nuiscle  arise  from  the  facia!  nerve  and  enter 
the  lids  near  the  outer  canthus.  The  cutaneous  filaments  of  the  ujijier  lid  are 
obtained  from  the  lacrymal,  supra-orbital,  and  supra-trochlear  nerve,  and  the 
lower  lid  derives  its  supply  from  the  infra-orbital  and  infra-trochlear  nerves. 
The  non-striated  mu.scular  tissue  of  the  lids  is  sujjplied  by  the  .sympathetic  nerve. 

The  lymphatics  of  the  eyelids  pass  to  the  parotid  and  submaxillary  lymph 
glands. 

The  conjunctiva  has  been  described. 

The  levator  palpebrae  superioris  muscle  arises  from  the  under  surface  of 
the  lesser  \\ing  of  the  sphenoid  bone  above  the  optic  foramen ;  its  fibers  terminate 


65G  SURGICAL  ANATOMY. 

in  a  broad,  thin  aponeurosis  which  is  inserted  into  the  upper  border  of  the 
superior  tarsal  cartilage.  This  muscle  runs  above  the  superior  rectus,  and  its 
upj^er  surface  is  in  relation  with  the  frontal  nerve  and  the  supra-orbital  artery. 

The  parotid  gland,  the  largest  of  the  salivary  glands,  weighs  from  one-half  to 
one  ounce.  It  is  situated  on  the  side  of  the  face,  and  extends  as  high  as  the 
zygoma  and  below  the  level  of  the  angle  of  the  lower  jaw.  It  covers  about  one- 
third  of  the  masseter  muscle,  and  extends  backward  to  the  external  auditory 
meatus,  the  mastoid  process,  and  the  sterno-mastoid  muscle.  It  is  lodged  in  the 
space  between  the  ramus  of  the  lower  jaw  and  the  mastoid  process.  This  space — 
known  also  as  the  bed  of  the  parotid  gland — can  be  increased  in  size  by  extending, 
and  diminished  by  flexing,  the  head.  With  tlie  mouth  wide  open — in  Avhich  posi- 
tion the  angle  of  the  jaw  is  carried  backward  and  the  condyle  forward — the  width 
of  the  space  is  diminished  below,  but  increased  above.  The  size  of  the  space  is 
influenced  by  the  age  of  the  individual.  In  the  infant,  owing  to  the  obliquity  of 
the  ramus  and  the  absence  of  the  angle  of  the  lower  jaw,  it  is  broader,  in  propor- 
tion, below.  In  advanced  age,  when  the  teeth  have  fallen  out,  thus  allowing 
the  angle  of  the  lower  jaw  to  project  forward,  the  space  is  broader  below.  When 
operating  in  this  space  these  facts  should  be  kept  in  mind,  as  it  may  be  necessary 
to  take  advantage  of  them.  The  gland  has  three  large  processes  or  lobes :  one, 
the  glenoid  lobe,  extends  upward  into  the  posterior  part  of  the  glenoid  cavity  of 
the  temporal  bone  which  it  occupies ;  another,  the  pterygoid  lobe,  extends  forward 
beneath  the  ramus  of  the  lower  jaw,  between  the  external  and  internal  pterygoid 
muscles ;  the  third  process,  the  carotid  lobe,  passes  behind  the  styloid  process 
and  beneath  the  mastoid  process  and  the  sterno-mastoid  muscle,  coming  in 
contact  with  the  internal  jugular  vein  and  the  internal  carotid  artery.  From 
the  relation  wliich  the  carotid  lobe  holds  to  the  internal  jugular  vein,  it  follows 
that  swelling  of  the  gland,  as  in  mumps,  may  cause  passive  congestion  of  the 
brain  by  compression  of  tliat  vein.  Tlie  anterior  margin  of  the  parotid  gland 
overlaps  the  masseter  muscle,  and  a  detached  j)ortion  of  the  gland  (soda  parotidis) 
lies  over  that  muscle  in  relation  with  the  upper  border  of  Stenson's  duct. 
From  the  position  which  the  parotid  gland  holds  with  reference  to  the  temporo- 
maxillary  articulation  it  follows  that,  in  inflammation  of  the  gland,  movement  of 
the  arlieulation  is  attended  by  l>ain  ;  tlie  extent  to  which  the  lower  jaw  can  be 
depressed  under  these  circumstances  is  dependent  upon  the  amount  of  swelling. 

Parotid  fascia. — Tlie  parotid  gland  is  covered  by  a  dense  and  strong  layer  of 
fascia — a  prolongation  of  the  sujierficial  layer  of  the  deep  cervical  fascia,  and 
called  the  parotid  fascia.  It  is  attached  above  to  the  zygoma,  and  is  continuous 
in  front  with  the  fascia  (■o^•ering  the  masseter  muscle.  From  the  parotid  fascia 
nunicidus  processes  are  sent  into  the  substance  of  the  gland  to  support  its  lobules. 


FACE.  657 

The  deep  fascia  of  the  neck  also  sends  beneath  the  gland  a  process  continuous  witli 
the  stylo-maxillary  ligament,  which  separates  the  parotid  from  the  submaxillary 
gland.  The  fibrous  envelop  of  the  parotid  gland  is  incomplete  above  and  in 
front,  where  its  cavity  is  in  communication  with  the  pterygo-maxillary  region.  In 
parotid  abscess  the  pus  may,  on  account  of  this  gap  in  the  fascial  envelop, 
extend  into  the  pterygo-maxillary  region,  and  by  way  of  the  latter  into  the  tem- 
poral fossa,  or  to  the  side  of  tlie  pharynx,  meeting  with  less  resistance  in  taking 
either  of  these  directions  than  in  attempting  to  reach  the  surface.  The  ab.scess 
may,  however,  extend  into  the  neck  by  ulcerating  through  the  layer  of  fascia 
beneath  the  gland.  ]\Iany  cases  of  retro-pharyngeal  abscess  are  attended  by 
swelling  in  the  parotid  region.  Retro-pharyngeal  growths — as,  for  example, 
sarcomata,  when  they  have  attained  any  size — cause  bulging  of  the  inirotid  region  ; 
and,  conversely,  tumors  of  the  parotid  may  bulge  into  the  pharynx.  The  severe 
pain  in  a  rapidly  growing  tumor  or  abscess  of  the  gland  is  due  to  the  density  of 
the  fascia  covering  it.  This,  too,  makes  it  difficult  to  detect  fluctuation  early.  It 
also  explains  why  the  pus  in  a  parotid  abscess  is  so  slow  to  find  its  way  to  the 
surface,  and  wliy  an  early  opening  should  be  made.  The  intimate  relation 
existing  between  the  parotid  gland,  the  external  auditory  meatus,  and  the 
temporo-maxillarjf  articulation  is  to  be  borne  in  mind,  as  a  parotid  abscess  may 
open  into  the  meatus  or  cause  involvement  of  the  joint. 

Purulent  meningitis  and  thrombosis  of  the  cranial  sinuses  may  be  caused 
when  pus  finds  its  way  through  the  foramina  at  the  base  of  the  skull. 

The  sensory  nerves  supplying  the  parotid  gland  are  the  auriculo-temporal 
branch  of  the  inferior  maxillary  nerve,  the  great  auricular  branch  of  the  cervical 
plexus,  the  facial  nerve,  and  branches  from  the  carotid  plexus  of  the  sympathetic 
nerve.  In  painful  affections  of  the  gland  the  pain  is  apt  to  be  referred  to  the  areas 
of  distribution  of  these  nerves. 

The  parotid  lymphatic  glands. — Lj'ing  upon  the  surface  of  the  parotid  gland 
(in  front  of  the  cartilage  of  the  ear,  and  close  to  the  root  of  the  zygoma)  are  one 
or  more  superficial  lymphatic  glands,  enlargement  of  whicli  must  not  be  mistaken 
for  a  similar  condition  of  tlie  parotid  gland  itself 

Contents  of  the  parotid  gland. — The  parotid  gland  is  important,  not  only  on 
account  of  its  function,  of  the  position  which  it  occupies,  and  of  the  relation  it  bears 
to  tlie  surrounding  parts,  but  also  because  important  structures  are  found  in  it. 
These  structures  are,  from  without  inward  :  The  facial  nerve,  passing  from  behind 
forward  ;  the  temi-oro-maxillary,  superficial  temporal,  internal  maxillary,  and 
posterior  auricular  veins ;  the  commencement  of  the  external  jugular  vein ;  the 
external  carotid  artery  which  supplies  branches  to  the  gland  and  divides  at  the 
neck  of  the  lower  jaw  into  its  two  terminal  branches — the  temporal  and  internal 


658  SURGICAL  ANATOMY. 

maxillary  arteries  ;  the  terminal  part  of  the  great  auricular  nerve  ;  and  one  or  two 
lymphatic  glands.  The  posterior  auricular  branch  of  the  external  carotid  artery 
and  the  transverse  facial  branch  of  the  temporal  artery  arise  in  the  substance  of 
the  gland. 

The  parotid  gland  is  separated  from  the  internal  carotid  artery,  from  the 
internal  jugular  vein,  and  from  the  pneumogastric,  glosso-pharyngeal,  and  hypo- 
glossal nerves  by  a  thin  layer  of  fascia ;  therefore  in  stab  wounds  of  the  parotid 
region  involving  one  of  the  two  carotid  arteries  it  may  be  difficult,  at  first,  to  tell 
which  of  the  two  vessels  has  been  wounded. 

From  an  anatomic  point  of  view  it  is  difficult  to  see  how  complete  removal 
of  the  parotid  gland  is  possible,  yet  the  operation  has  been  done  so  many  times  by 
skilful  surgeons  that  there  is  no  question  of  its  feasibility.  Doubtless,  as  long  ago 
suggested  by  Fiihrer,  Avhen  the  gland  becomes  the  site  of  a  neoplasm  it  becomes 
more  compact,  its  processes  being  rounded  off,  as  it  were,  and  lifted  away  from  the 
surrounding  structures. 

Complete  removal  of  the  parotid  gland  results  in  paralysis  of  the  muscles  of 
expression,  for  it  is  impossible  to  avoid  dividing  the  facial  nerve.  The  author  has 
seen  a  growth  of  the  overlying  lymphatic  gland  cause  facial  paralysis  from  pressure, 
and  thus  so  closely  simulate  a  parotid  neoplasm  as  to  be  pronounced  a  tumor  of 
the  parotid  gland  ;  but  upon  the  removal  of  the  growth  the  parotid  gland  was  seen 
to  occupy  the  bottom  of  the  wound,  and  to  be  in  a  very  much  atrophied  condition. 

Socia  parotidis. — Tliat  portion  of  the  parotid  gland  resting  upon  the  masseter 
muscle  above  the  parotid  duct  (Stenson's  duct),  and  quite  separate  from  the  gland 
proper,  is  known  as  the  socia  parotidis.     Its  duct  empties  into  Stenson's  duct. 

Stenson's  duct. — Running  about  one  finger's  breadth  below  the  zygoma,  or  in 
a  line  drawn  from  the  lower  margin  of  the  concha  to  a  point  midway  between  the 
free  margin  of  the  upper  lip  and  the  ala  of  the  nose,  is  the  duct  of  the  parotid 
(Stenson's  duct).  It  is  about  two  inches  in  length  by  one-eighth  of  an  inch  in 
diameter,  being  narrowest  at  its  point  of  communication  with  the  mouth.  It  lies 
between  the  transverse  facial  artery  above  and  the  buccal  branch  of  the  facial 
nerve  below.  The  duct  runs  over  the  masseter  muscle,  turning  abruptly  inward 
at  its  anterior  border,  passes  through  the  mass  of  fat  overlying  the  buccinator 
muscle  ami  l)rnoatli  the  facial  vein,  and  pierces  the  buccinator  muscle  to  open 
into  llie  moutli  opimsito  tlic  crown  of  the  second  molar  tooth  of  the  upper  jaw. 
1'lie  turn  of  tlie  duct  around  tlie  anterior  border  of  the  masseter  muscle  must  be 
borne  in  mind  when  passing  a  probe  into  the  duct  from  the  mouth.  In  opening 
a  parotid  abscess  the  incision  should  be  horizontal,  and  should  be  made  below  the 
line  of  the  duct  and  in  front  of  the  posterior  border  of  the  ramus  of  the  lower 
jaw.     Failure  to  observe  this  caution   may  result  in    section  of  the    duct,  w'ith 


FACE.  659 

resulting  fii^tula  (salivary  fistula).  It  is  also  advisable  to  take  every  precaution 
against  cutting  througli  the  gland  tissue  in  opening  a  parotid  abscess,  for  these 
collections  of  pus,  like  those  of  the  niammtc,  generally  atl'ect  the  connective  tissue 
of  the  gland  and  not  its  substance  or  parenchyma. 

Stenson's  duct  may  be  divided  into  a  masseteric  and  a  buccal  portion.  The 
masseteric  portion  rests  upon  the  niasseter  muscle  and  the  /jucca I  part  extends  from 
the  anterior  border  of  the  masseter  muscle  to  the  termination  of  the  duct  in 
the  mucous  membrane  of  the  cheek.  Fistuke  of  the  masseteric  part  are  closed 
with  difficulty,  whereas  fistula;  of  the  buccal  portion  are  remedied  by  making  an 
opening  from  the  duct  into  the  mouth  on  the  j^roximal  side  of  the  fistula.  The 
author  has  successfully  treated  fistula^  of  the  buccal  portion  by  exposing  the  duct 
through  an  incision  in  the  cheek,  dividing  the  dvict  at  the  proximal  side  of  the 
fistula,  freeing  the  duct  from  the  surrounding  tissues,  and  stitching  the  divided 
end  to  the  margins  of  an  opening  made  in  the  mucous  memlsrane  of  the  mouth. 

Dissection. — Before  turning  over  the  head  to  make  the  dissection  of  the  oppo- 
site side  of  the  face,  the  parotid  gland  should  be  removed  entire  ;  this  operation  will 
convey  an  approximate  idea  of  the  difficulties  which  would  attend  the  removal  of 
the  gland  in  the  living  subject.  The  masseter  muscle  should  then  be  exposed  and 
the  external  ear  dissected.  In  exposing  the  parotid  gland,  its  fascial  covering  is 
seen  to  be  continuous  anteriorly  with  the  fascia  covering  the  masseter  muscle,  and, 
therefore,  the  parotid  and  masseteric  fascice  are  practically  one.  These  fasciae  are 
derived  from  the  superficial  layer  of  the  deep  cervical  fascia,  which  is  continued 
upward  over  the  body  of  the  lower  jaw  and  attached  above  to  the  zygoma.  By 
displacing  the  parotid  gland  forward  and  removing  the  foscia  covering  that  portion 
of  the  masseter  muscle  in  advance  of  the  gland,  the  muscle  itself  is  exposed. 

The  masseter,  the  most  superficial  of  the  muscles  of  mastication,  is  of  quad- 
rate form,  and  arises  as  two  portion.? — a  large,  tendinous,  superficial  layer,  and  a 
small,  fleshy,  deep  layer.  The  superficial  sheet  arises  from  the  anterior  two-thirds 
of  the  lower  border  of  the  zygomatic  arch  and  from  tlie  lower  border  of  the  malar 
bone  ;  its  fibers  pass  downward  and  l)ackward  to  be  inserted  into  the  outer  surface 
of  the  angle  and  lower  portion  of  the  ramus  of  the  lower  jaw.  The  deep  sheet 
arises  from  the  posterior  third  of  the  lower  border  and  all  of  the  inner  surface 
of  the  zygoma ;  it  passes  downward  and  forward  to  be  inserted  into  the  upper 
half  of  the  ramus  and  the  outer  surface  of  the  coronoid  process  of  the  lower  jaw. 
The  posterior  portion  of  the  muscle  is  concealed  by  the  parotid  gland.  In  relation 
with  the  superficial  surface  of  the  muscle  are  the  orbicularis  palpebrarum,  the 
zj'gomatici  major  and  minor,  and  the  platysma  myoides  muscle,  the  anterior 
margin  of  the  parotid  gland,  Stenson's  duct,  the  tran.sverse  facial  vessels,  branches 
of  the  facial  nerve,  and,  at  its  anterior  inferior  angle,  the  facial  vein.     In  relation 


660  SURGICAL  ANATOMY. 

with  its  deep  surface  are  the  buccal  pad  of  fat,  the  buccinator  and  a  small  part  of 
the  temporal  muscle,  the  masseteric  artery  and  nerve,  and  the  ramus  of  the  jaw. 

Blood  Supply. — From  the  masseteric  branch  of  the  internal  maxillary,  the 
transverse  facial,  and  the  facial  artery. 

Nerve  Supply. — From  the  masseteric  nerve,  a  branch  of  the  inferior  maxil- 
lary division  of  the  trifacial  nerve. 

Action. — It  raises  the  lower  jaw,  as  in  mastication. 

The  External  Ear  consists  of  the  pinna,  or  auricle,  and  of  the  tube  leading  to 
the  tympanic  membrane — the  external  auditory  canal.  The  pinna  collects  the 
vibrations  of  sound,  and  the  canal  conveys  them  to  the  tj-mpanum. 

The  pinna,  or  auricle,  is  pyriform  in  shape,  with  its  concave  surface  directed 
outward  and  sliglitly  forward,  and  consists  of  a  layer  of  yellow  fibro-cartilage 
having  an  uneven  surface  covered  with  integument.  It  is  attached  to  the  com- 
mencement of  the  external  auditory  meatus,  and  consists  of  various  elevations  and 
depressions,  each  elevation  having  a  corresponding  depression  on  its  opposite 
surface.  The  deep  hollow  in  its  center,  which  is  wide  above  and  narrow  below,  is 
called  the  concha.  The  concha  leads  to  the  commencement  of  the  external  audi- 
tory meatus,  and  is  partly  di\ided  into  two  by  the  beginning  of  the  helix.  The 
helix  passes  upward,  forms  the  rim  of  the  pinna,  and  terminates  behind  in  the 
lobule,  which  is  the  lowest  portion  of  the  auricle  and  consists  of  fatty  and  areolar 
tissue.  Internal  to  the  helix  is  the  depression  called  the  fossa  of  the  helix,  or 
scaphoid  fossa.  Internal  to  the  fossa  of  the  helix  is  the  ridge  bounding  the  concha 
behind  and  above.  This  ridge  is  called  the  anthelix ;  it  begins  above  the  lobule, 
at  a  small  prominence,  the  antitragus,  and  bifurcates  at  the  upper  part  of  the 
auricle,  emijracing  a  small  triangular  dej^ression — the  fossa  of  the  anthelix.  In 
front  of  the  concha  and  projecting  backward  over  the  orifice  of  the  external  audi- 
tory  meatus  is  the  tragus.  Between  the  tragus  and  antitragus  is  a  notch — the 
incisura  intertragica. 

Dissection. — The  integument  should  be  removed  from  the  pinna,  when  the 
small  and  rudimentary  muscles  and  the  cartilage  will  be  exposed. 

The  integument  of  the  pinna  is  thin  and  delicate.  It  contains  sebaceous 
glands  which  are  largest  in  the  conclia,  and  here  the  ducts  of  the  glands  often 
become  filled  with  foreign  matter,  giving  rise  to  the  so-called  comedones. 

Upon  the  posterior  aspect  of  the  auricle  the  integument  is  less  firmly  attached 
to  the  underlying  parts  than  el.scwhere,  consequently  inflammatory  swellings,  as  in 
erysipelas,  are  most  marked  in  this  situation. 

Extravasations  of  blood  beneath  the  skin  are  not  uncommonly  seen  as  the 
result  of  l)lows  u|iun  tin/ car;  tliese  so-called  othematomata  have  been  most  often 
observed    in    in.sane   persons   and   in   prize-fighters.     According   to  "N'irchow  and 


PLATE  CLXII 


Hulix 


Fossa  of  helix 


Darwin's  tubercle 


Antihelix 


Concha 


Antitragus 

Lobule 


Fossa  of  antihelix 


Tragus 


ncisura  intertragica 


PINNA. 
661 


PLATE  CI,XIV. 


Helix 


Darwin's  tubercle 


Helicis  major  m. 


Obliquus  auris  m. 


Transversus  auris  m. 


Fissure  of  Santorini 


Antitragicus  m. 
Processus  caudatus 


INTRINSIC  MUSCLES  OF  PINNA. 
663 


FACE.  665 

Luihviix  Meyor,  degenerative  changes  in  the  hlood-vessels  and  cartilage  favor  the 
occurrence  of  such  extravasations.  Cicatricial  contractions  may  cause  deftnniity 
of  the  pinna  after  the  absorption  or  evacuation  of  such  hematomata.  Under 
the  integument  of  the  lobule  gouty  deposits  (tophi)  are  sometimes  found. 

The  Muscles  wliich  move  the  cartilage  of  the  ear  as  a  whole,  three  in  number, 
have  been  described  under  the  dissection  of  the  scalp.  Tlie  muscles  proper  of  the 
auricle,  whiih  extend  from  one  part  of  the  cartilage  to  another,  are  six  in  number 
— namely,  the  nuiscle  of  the  tragus,  the  muscle  of  the  antitragus,  the  small 
muscle  of  the  helix,  the  large  muscle  of  the  helix,  the  transverse  muscle  of  the 
auricle,  and  tlie  oblique  muscle  of  the  auricle. 

The  tragicus,  the  muscle  of  the  tragus,  is  situated  upon  the  outer  surface  of 
the  tragus. 

The  antitragicus,  the  muscle  of  the  antitragus,  arises  from  the  outer  part  of 
the  antitragus ;  its  fibers  pass  upward  and  are  inserted  into  the  posterior  extremity 
of  the  helix. 

The  helicis  minor,  the  small  muscle  of  the  helix,  is  attached  to  the  commence- 
ment of  the  helix  and  extends  into  the  concha.     This  muscle  is  sometimes  ab.sent. 

The  helicis  major,  the  large  muscle  of  the  helix,  is  situated  upon  the  anterior 
margin  of  the  lielix  ;  it  arises  above  the  small  muscle  and  is  inserted  into  the  front 
of  the  helix,  where  it  begins  to  curve  backward. 

The  transversus  auris,  the  transverse  muiscle  of  the  auricle,  is  situated  on 
the  back  of  the  auricle  in  the  depression  between  the  helix  and  the  convexity  of 
the  concha  ;  it  arises  from  the  convexity  of  the  concha  and  is  inserted  into  the  back 
of  the  helix. 

The  obliquus  auris,  the  oblique  muscle  of  the  auricle,  extends  from  the  upper 
back  part  of  the  concha  to  the  convexity  immediately  above  it. 

Nerve  Supply. — The  pinna  derives  its  nerve  .supply  from  the  auriculo- 
temporal, the  posterior  auricular,  the  auricular  branch  of  the  pneumogastric 
(Arnold's  nerve),  the  occipitalis  minor,  and  the  auricularis  magnus  nerve. 

Action. — The  muscles  of  the  helix  assist  those  of  the  tragus  and  antitragus 
in  retarding  the  passage  of  sound  to  the  meatus. 

Blood  Supply. — The  pinna  is  well  supplied  with  freely  anastomosing  vessels — 
branches  of  the  po.sterior  auricular,  temporal,  and  occipital  arteries.  The  veins 
accompany  the  corresponding  arteries. 

The  numerous  lymphatics  empty  into  the  pre-auricular  glands  and  into  those 
situated  upon  the  insertion  of  the  .sterno-mastoid  muscle. 

The  cartilage  of  the  pinna  is  a  single  piece,  and  presents  the  irregularities 
characteristic  of  the  external  ear.     It  is  prolonged  inward  in  the  shape  of  a  tube 
S— 43 


G66  -  SURGICAL  ANATOMY. 

which  forms  the  outer  part  of  the  external  auditory  meatus  ;  it  is  wanting  between 
the  tragus  and  the  commencement  of  the  helix,  the  interval  between  them  being 
occupied  by  fibrous  tissue.  Where  the  helix  makes  its  first  bend,  at  the  front  part 
of  the  pinna,  is  a  conic  projection  of  the  cartila.ge — the  process  of  the  helix.  At 
the  highest  part  of  the  helix  there  is  not  infrequently  to  be  seen  another  conic 
projection,  to  which  Darwin  first  called  attention  ;  he  regards  it  as  tlie  represen- 
tative of  the  extreme  tip  of  the  pinna  of  some  of  the  lower  animals.  At  certain 
places  the  cartilage  is  incomplete ;  these  gaps  are  known  as  fissures,  and  are 
located  as  follows :  at  the  anterior  part  of  the  pinna,  behind  the  process  of  the 
helix  (fissure  of  the  helix) ;  on  the  surface  of  the  tragus  ;  and  at  the  lower  part  of  the 
anthelix.  In  the  piece  of  cartilage  which  forms  the  outer  part  of  the  meatus  are 
two  fissures — the  fissures  of  Santorini.  The  pinna  is  attached  anteriorly  to  the 
root  of  the  zygoma  and  posteriorly  to  the  mastoid  process  by  bands  of  fibrous 
tis.sue ;  in  addition,  there  are  various  intrinsic  ligaments,  uniting  the  different  parts. 

Dissection. — Turn  the  head  to  the  opposite  side,  fix  it  with  hooks,  and  work 
out  the  facial  nerve  and  the  branches  of  the  trifacial  nerve  which  make  their  exit 
upon  the  face.  Expose  the  facial  nerve  by  a  longitudinal  incision  carried  into  the 
substance  of  the  parotid  gland  in  front  of  the  lobe  of  the  ear,  cutting  away  a  little 
of  the  gland  Avith  each  movement  of  the  knife  until  the  nerve  is  seen,  when  it  can 
be  traced  both  backward  and  forward. 

The  facial  nerve  (the  seventh  cranial)  is  the  motor  nerve  of  the  face ;  it 
consists  of  three  portions — the  intra-cranial,  the  temporal,  and  the  facial.  The 
facial  portion,  that  which  concerns  us  in  this  dissection,  supplies  all  the  muscles  of 
expression  and  the  platysma,  the  buccinator,  the  occipito-fi;ontalis,  the  attrahens, 
attolens,  and  retrahens  aurem,  the  posterior  belly  of  the  digastric,  and  the  stylo- 
hyoid. 

A  line  drawn  from  the  anterior  border  of  the  mastoid  process  opposite  the 
base  of  tlie  loliule  of  the  ear  downward  and  forward  across  the  face  for  about  one 
inch  will  represent  the  course  of  the  facial  portion  of  the  trunk  of  the  nerve. 

Course. — It  leaves  the  cranial  cavity  through  the  internal  auditory  meatus  in 
company  with  the  auditory  nerve,  the  pars  intermedia  of  Wrisberg,  and  the 
auditory  artery.  Reaching  the  bottom  of  the  internal  auditory  meatus  it  enters 
the  facial  canal,  or  aqueductus  Fallopii  of  the  temporal  bone,  from  which  it  makes 
its  exit  by  way  f)f  tlio  stylo-mastoid  foramen.  Passing  downward  and  forward 
from  the  foramen  it  enters  tlie  parotid  gland,  crosses  the  external  carotid  artery, 
gives  off  a  posterior  auricular,  a  digastric,  and  a  stylo-hyoid  branch,  and  terminates 
in  two  divisions — (lie  tcniporo-facial  and  the  cervico-facial. 

The  posterior  auricular  nerve,  the  first  extra-cranial  branch,  passes  ujjward 
in  the  groove  between  the  ear  and  the  mastoid  process,  communicates  with  the 


PLATE  CLXV. 


Temporal  br.  of  orbital  n 
Supraorbital  n 
Supratrochlear  n 


Malar  br.  of  facial  n. 


Temporal  br.  of  facial  n. 


Great  occipital  n. 


Small  occipital  n. 


Auriculo-temporal  n. 
nfraorbital  br.  of  facial  n. 

Great  auricular  n. 


Supramaxillary  br.  of  facial  n. 
Buccal  br.  of  facial  n. 


nfraorbital  br.  of  superior  maxillary  n. 


Mental  n. 
Infratrochlear  n. 


Nasal  n. 


NERVES  OF  SCALP  AND  FACIAL  NERVE. 
667 


FACE.  6fi9 

auricular  brancli  of  tlie  imoumogastric  and  the  great  auricular  branch  of  the 
cervical  plexus,  and  divides  into  an  auricular  and  an  occii)ital  l)rancli.  The 
auricular  Ijranch  supijlics  the  attolens  and  retrahens  aurem  muscles.  The 
occipital  branch  passes  along  the  sujwrior  curved  lino  of  the  occijiital  bone, 
supplies  the  occipitalis  muscle,  and  communicates  M'ith  the  small  occipital  branch 
of  the  cervical  plexus. 

The  digastric  branch  supplies  the  posterior  belly  of  the  digastric  muscle,  and 
communicates,  by  a  twig  which  usually  perforates  that  muscle,  with  the  glosso- 
pharyngeal nerve. 

The  stylo-hyoid  branch  is  longer  than  the  digastric  ;  it  enters  the  stylodiyoid 
muscle  about  its  middle,  and  communicates  with  tilaments  of  the  sympathetic 
nerve  on  the  external  carotid  artery. 

The  temporo-facial,  the  larger  of  the  two  terminal  divisions,  runs  obliquely 
upward  and  forward  through  the  substance  of  the  jmrotid  gland,  crosses  the 
external  carotid  artery  and  the  temporo-maxillary  vein,  and  breaks  up  into  the 
temporal,  malar,  and  infra-orbital  branches.  It  communicates  with  the  auriculo- 
temporal nerve.  The  temporal  branches  ascend  obliquely  over  the  zygomatic 
arch  to  supply  the  tensor  tarsi,  the  orbicularis  palpebrarum,  the  corrugator 
supercilii,  the  frontalis,  and  the  attolens  and  attrahens  aurem  muscles,  and  to 
communicate  with  the  supra-orbital,  the  lacrymal,  and  the  auriculo-temporal 
nerve,  and  with  the  temporo-malar  branch  of  the  superior  maxillary  nerve. 

The  malar  branches  run  across  the  malar  bone  to  the  outer  angle  of  the 
orbit  to  supply  the  orbicularis  jialpebrarum  muscle,  and  communicate  with  the 
lacrymal  and  the  supra-orbital  nerve  and  with  the  infra-orl)ital  and  temporo- 
malar  branches  of  the  superior  maxillary  nerve.  The  infra-orbital,  the  largest 
branch,  gives  off  a  superficial  and  a  deep  set  of  branches,  wdiich  pass  transversely 
forward  over  the  masseter  and  beneath  the  zygomatic  muscles  to  supply  the 
zygomatic  muscles,  the  elevators  of  the  upper  lip,  the  muscles  of  the  nose,  and 
the  orbicularis  oris  muscle.  The  superficial  branches  communicate  with  tlie  nasal 
and  infra-trochlear  nerves  which  are  derived  from  the  ophthalmic  division  of  the 
trifacial  nerve.  The  deep  liranches  form  a  loo]i  with  the  l)uccal  liraneh  of  tlie 
cervico-facial  division,  and  pa.ss  beneath  the  levator  labii  .superioris  muscle,  where 
they  unite  with  the  infra-orbital  branch  of  the  superior  maxillary  nerve,  forming 
the  infra-orbital  plexus. 

The  cervico-facial,  the  smaller  of  the  two  terminal  divisions  of  the  facial 
nerve,  is  joined  by  a  branch  of  the  great  auricular  nerve  while  in  the  substance  of 
the  parotid  gland.  It  j^asses  obliquely  downward  toward  the  angle  of  the  lower 
jaw,  crosses  the  external  carotid  artery  and  the  temporo-maxillary  vein,  and  divides 
into  buccal,  supra-maxillary,  and  infra-maxillary  branches.     The  buccal  branches 


670  SURGICAL  ANATOMY. 

pass  forward  over  the  masscter  and  Imccinator  muscles  below  Stenson's  duct,  to  the 
angle  of  tlie  mouth,  to  sujjply  the  buccinator  and  orbicularis  oris  muscles,  and 
communicate  with  the  infra-orbital  nerve,  the  infra-orbital  branches  of  the 
temporo-facial  branch,  and  the  long  buccal  branch  of  the  inferior  maxillary  nerve. 
The  buccal  branch  of  the  facial  nerve  and  the  long  buccal  branch  of  the  inferior 
maxillary  nerve  form  a  plexus  over  the  buccinator  muscle  and  the  facial  vein. 
The  supra-maxillary  branch,  passes  downward  and  forward  over  the  masseter  muscle 
and  the  facial  artery,  and  beneath  the  platysma  myoides  and  the  depressor  muscles 
of  the  lower  lip.  It  supplies  the  muscles  of  the  lower  lip,  the  risorius,  and  the 
levator  menti,  and  communicates  with  the  buccal  branch  of  the  facial  and  the 
mental  branch  of  the  inferior  dental  nerve.  The  infra-maxillary  branch  emerges 
from  the  lower  border  of  the  parotid  gland  in  front  of  the  external  jugular  vein 
and  passes  downward  and  forward  toward  the  sternum  beneath  the  platysma 
myoides  muscle,  which  it  supplies.  It  communicates  with  the  great  auricular  and 
superficial  cervical  nerves — branches  of  the  cervical  plexus.  The  infra-maxillary 
branch  can  be  traced  when  dissecting  the  superficial  fascia  of  the  neck. 

The  pes  anserinus  (plexus  parotideus). — The  breaking  up  of  the  two  terminal 
divisions  of  the  facial  nerve  within  the  substance  of  the  parotid  gland  gives  rise 
to  a  plexus,  the  pes  anserinus  (goose's  foot). 

Bell's  palsy. — Paralysis  of  the  facial  nerve  is  known  as  Bell's  palsy,  and  may 
be  either  central  or  peripheral.  A  central  paralysis  is  due  to  involvement  of  the 
nucleus  of  the  nerve,  its  center  in  the  cortex  of  the  brain,  or  the  fibers  connecting 
these,  and  results  from  pressure,  as  by  hemorrhage,  abscess,  or  tumor ;  it  may  also 
be  brought  about  liy  degenerative  processes  in  the  brain.  A  peripheral  paralysis 
is  due  to  affection  of  the  trunk  of  the  nerve  within  the  cranial  cavity  by  tumors 
or  meningitis ;  within  the  facial  or  Fallopian  canal,  by  middle  ear  disease  or  frac- 
ture of  the  base  of  the  skull ;  external  to  the  stylo-mastoid  foramen,  by  a  growth 
at  the  stylo-mastoid  foramen,  rapidly  growing  tumors  or  abscess  of  the  parotid 
gland,  division  during  an  operation,  or  exposure  of  the  face  to  cold.  "When  the 
lesion  is  situated  beyond  the  origin  of  tlie  chorda  tympani  nerve  the  muscles 
of  expression  and  the  buccinator  muscle  on  the  same  side  of  the  face  become 
paralyzed,  the  mouth  is  drawn  to  the  opposite  side,  and  the  affected  side  of  the 
face  becomes  flattened  and  free  from  wrinkles.  Through  paralysis  of  the  orbicularis 
palpebrarum  muscle  the  eye  on  the  paralyzed  side  remains  open,  and  the  tears  run 
down  tlie  clicck.  The  anterior  naris  of  the  affected  side  is  smaller  in  appearance 
through  paralysis  of  the  nasal  muscles.  Paralysis  of  the  buccinator  muscle  causes 
the  food  to  collect  l)etween  the  cheek  and  the  teeth  of  the  affected  side.  Through 
paralysis  of  the  orbicularis  oris  muscle  the  saliva  dribbles  from  the  mouth,  and  the 
jiatient  can  not  whistle.     When  the  lesion  is  situated  in  the  aqueductus  Fallopii 


PLATE  CLXVI. 


OPERAIION  FOR  EXPOSURE  OF  FACIAL  NERVE. 
672 


PLATE  CLXVII. 


Supraorbital  a. 
Supraorbital  n. 
Frontal  a. 


Infraorbital  br.of  facial  n. 
Temporal  br.  of  orbital  n. 
Malar  br.of  facial  n. 

Temporal  br.of  facial  n. 

Temporal  fascia 


Auriculo-temporal  n. 
oral  a. 
iricular  a. 


facial  n. 


Mental  n!         Mental  a. 

Labial  br.  of  infraorbital  n' 


^Facial  a. 

Infraorbital  n. 
^  Palpebral  br.  of  infraorbital  n. 

ifraorbital  a. 
'Nasal  br.  of  infraorbital  n. 


TEMPORAL  FASCIA  AND   NERVES  OF  FACE, 
673 


FACE.  675 

and  altovc  tlie  origin  of  the  clionla  tympani  nerve,  there  is  loss  of  the  sense  of 
taste  in  the  anterior  two-thirds  of  tiie  tongvie  on  the  diseased  side,  and  through 
paralysis  of  the  sta})edius  muscle  loud  sounds  are  distressing.  When  the  lesion  is 
central  or  in  the  brain,  the  brow  and  eyelid  arc  not  affected — /.  c,  the  frontalis, 
corrugator  supercilii,  and  orbicularis  palpebrarum  muscles  are  not  involved.  This 
is  probably  due  to  escape  of  the  fibers  which  arise  from  the  nucleus  of  the  opposite 
side. 

Spasms,  both  tonic  and  clonic,  of  Ihe  muscles  supplied  by  the  facial  nerve 
may  occur.  Persistent  spasm  of  these  nuiscles  is  relieved  by  stretching  the  facial 
nerve. 

Operative  exposure  of  the  facial  nerve. — The  facial  nerve  is  exposed  by 
carrying  a  vertical  incision  from  in  front  of  the  mastoid  process  and  behind  the 
lobule  of  the  ear  downward  toward  the  angle  of  the  lower  jaw,  laying  Itare  first 
the  posterior  border  of  the  parotid  gland,  which  is  displaced  foiwanl,  and  then 
the  anterior  border  of  the  sterno-mastoid  muscle  at  its  insertion.  The  parotid 
gland  should  be  separated  from  the  mastoid  process  to  the  depth  of  about  one 
centimeter,  when  the  nerve  may  be  seen.  The  exact  location  of  the  nerve  in  the 
wound  can  be  ascertained  by  the  use  of  the  fiiradic  battery. 

The  trifacial  nerve. — The  branches  of  the  trifiicial  or  fifth  nerve  which 
make  their  exit  upon  the  face  are  the  supra-orbital  and  the  supra-trochlear  (pre- 
viously described),  the  lacrymal,  the  infra-orbital,  the  malar,  the  anterior  branch 
of  the  nasal,  and  the  mental  nerve. 

The  lacrymal  nerve,  the  smallest  of  the  ophthalmic  branches,  supplies  the 
lacrymal  gland,  and  freciuently  communicates  witli  the  temporal  branch  of  the 
temporo-malar  nerve  in  the  orl)it ;  it  sends  a  small  filament — the  palpebral — to 
the  skin  and  conjunctiva  around  the  outer  canthus  of  the  eye. 

The  infra-orbital  nerve,  the  terminal  branch  of  the  superior  maxillary 
division  of  the  trifacial  nerve,  emerges  from  the  infra-orbital  foramen  in  company 
with  the  infra-orbital  artery,  under  cover  of  the  levator  labii  supeiioris  muscle. 
It  immediately  divides  into  palpebral,  nasal,  and  labial  branches.  The  palpebral 
branches,  the  smallest,  pass  upward  beneath  the  orbicularis  palpebrarum  muscle, 
supply  the  lower  eyelid,  and  communicate  with  the  facial  and  the  malar  branch  of 
the  orbital  or  temporo-malar  nerve.  The  nasal  branches,  three  or  four  in  number, 
pass  inward  under  the  levator  labii  superioris  ala-que  nasi  muscle  to  supply  the 
side  of  the  nose,  and  communicate  with  the  external  (naso-labial)  branch  of  the 
nasal  nerve.  The  labial  braiiclic.i,  usually  four,  arc  larger  than  the  palpebral  or 
nasal  Ijranches,  and  descend  beneath  the  levator  labii  superioris  muscle  to  supply 
the  upper  lip.  Beneath  the  levator  labii  superioris  the  branches  assist  in  forming 
the  infra-orbital  plexus.     (See  description  of  plexus  under  Facial  Nerve.) 


676.  SURGICAL  ANATOMY. 

The  infra-orbital  artery,  a  branch  of  the  internal  maxillary,  accompanies  the 
infra-orbital  nerve  through  the  infra-orbital  foramen,  and  divides  into  l)ranches 
which  are  distributed  like  those  of  the  nerve.  It  anastomoses  with  the  transverse 
facial,  facial,  and  ophthalmic  arteries. 

The  infra-orbital  vein  communicates  with  the  facial  vein  in  front,  and 
empties  into  the  pterygoid  plexus  of  veins. 

The  malar  division  of  the  orbital  or  temporo-malar  branch  of  the  superior 
maxillary  nerve  makes  its  exit  through  a  foramen  in  the  malar  bone,  pierces  the 
orbicularis  palpebrarum  muscle,  and  supplies  the  skin  of  the  cheek  covering  the 
malar  bone.  It  communicates  with  the  facial  and  the  palpebral  branches  of  the 
infra-orbital  nerve. 

The  external  or  terminal  branch  of  the  nasal  nerve,  also  known  as  the 
naso-labial,  emerges  between  the  nasal  bone  and  the  lateral  cartilages  of  the  nose, 
supplying  the  tip  of  the  nose  as  it  descends  beneath  the  compressor  narium  muscle. 
It  communicates  with  the  infra-orbital  branches  of  the  facial  and  trifacial  nerves. 

The  mental  nerve,  the  continuation  of  the  inferior  dental,  emerges  from  the 
mental  foramen  in  company  with  the  mental  artery.  It  divides  beneath  the  de- 
pressor anguli  oris  muscle  into  three  branches,  the  smallest  of  which  descends  to 
supply  the  chin,  while  the  other  two  ascend  to  supply  the  lower  lip.  It  inosculates 
with  the  supra-maxillary  branch  of  the  facial  nerve. 

The  mental  artery,  the  terminal  portion  of  the  inferior  dental,  supplies  the 
chin  and  anastomoses  with  the  submental,  inferior  labial,  and  inferior  coronary 
arteries. 

PTERYGO-MAXILLARY  REGION. 

The  pterygo-maxillary  region  is  the  space  included  between  the  ramus  of  the 
lower  jaw,  externally ;  the  lateral  wall  of  the  pharynx  and  the  pterygoid  process 
of  the  sphenoid  bone,  internally  ;  the  zygomatic  surface  of  the-  superior  maxilla, 
anteriorly  ;  and  the  lower  surface  of  the  greater  wing  of  the  sphenoid  and  the 
adjacent  temjioral  bone,  above.  The  posterior  limit  of  the  space  is  represented 
by  a  plane  passing  directly  inward  from  the  posterior  border  of  the  ramus  of 
the  inferior  maxilla  to  the  pharynx. 

Dissection. — The  zygomatic  arch  should  be  removed  by  sawing  through  the 
zygomatic  jirocesscs  of  both  the  malar  and  temporal  l)nnes.  In  tlie  latter,  the 
point  selected  sliould  l>e  ju.st  in  front  of  the  tubercle  of  the  zygoma.  Reflect 
the  masseter  muscle  from  the  ramus  of  the  inferior  maxilla,  carrying  the  zygoma 
with  it ;  locate  the  masseteric  artery  and  nerve  which  pass  through  the  sigmoid 
notch  of  the  lower  jaw  ;  trace  them  into  the  masseter  muscle  as  far  as  possible, 
and  then   .sever   them.     A   portion   of  the   ramus  of  the   lower  jaw   should   be 


PLAIE  CLXVIll. 


Anterior  deep  temporal  a 
Superior  maxillary  n. 


Anterior  temporal  n. 
Posterior  temporal  n 

Posterior  deep  temporal  a. 
Masseteric  n. 

Temporal  m. 


Orbital  n. 
infraorbital  a 


Buccinator 


Auriculo-temporal  n. 

Superficial  temporal  a. 
sseteric  a. 
sverse  facial  a. 
al  maxillary  a. 
dental  a. 
uricular  a. 
tal  n. 
tid  a. 


Posterior  superi 

Alveolar  a! 
Buccal  a' 
Buccal  n 
External  pterygoid  m'. 
Lingual  n 


PTERYGOID  MUSCLES  AND   INTERNAL   MAXILLARY  ARTERY. 
G78 


FACE.  079 

removed  in  the  following  manner :  With  Hcy's  saw  cut  downward  behind 
the  last  molar  tooth,  halt'  way  thnnigh  the  body  of  the  jaw,  then  Ijackward 
to  near  the  angle.  Discard  the  saw  M-hen  it  reaches  the  cancellous  tissue, 
and  use  the  chisel  to  avoid  division  of  the  inferior  dental  vessels  and  nerve. 
The  saw  should  now  be  directed  downward  from  the  sigmoid  notch,  just  in  front 
of  the  neck  of  the  jaw,  through  the  ramus  to  the  end  of  the  incision  in  the  body 
of  the  bone.  The  removal  of  this  portion  of  the  inferior  maxilla  is  tedious,  as  the 
internal  pterygoid  muscle,  internal  lateral  ligament,  and  the  inferior  dental  vessels 
and  nerve  oppose  elevation  of  the  section  of  bone  thus  separated.  Remove  the 
posterior  inferior  corner  of  the  section  of  the  ramus  with  bone  forceps  as  far  as 
the  inferior  dental  canal,  which  contains  the  inferior  dental  vessels  and  nerve ; 
then  reflect  the  b(ine  with  the  lower  jiortion  of  the  temporal  muscle,  taking  care 
to  avoid  destroying  the  mylo-hyoid  arterj'  and  nerve  which  arise  from  the  inferior 
dental  artery  and  nerve,  near  the  inferior  dental  foramen,  and  pass  downward  and 
forward  in  a  groove  on  the  internal  surface  of  the  ramus.  In  making  this 
dissection  it  is  advisable  to  use  the  back  of  the  point  of  the  scalpel,  as  the  vessels 
and  nerves  are  small,  of  delicate  structure,  and  are  easily  severed. 

The  contents  of  the  pterygo-maxillary  region  are  the  internal  and  external 
pterygoid  muscles,  the  internal  maxillary  artery  with  some  of  its  branches  and 
their  companion  veins,  the  pterygoid  plexus  of  veins,  the  infei'ior  maxillary  nerve, 
and  the  following  branches  of  that  nerve :  The  anterior  and  posterior  deep 
temporal,  long  buccal,  masseteric,  internal  and  external  pterj'goid,  inferior  dental, 
auriculo-temporal,  ami  lingual  nerves,  the  chorda  tympani  nerve,  a  portion  of  the 
parotid  gland,  the  internal  lateral  ligament  of  the  lower  jaw,  and  the  internal 
maxillary  lymphatic  glands. 

The  internal  maxillary  artery,  which  is  closely  related  to  the  nerves  of  this 
region,  passes  forward  either  over  or  behind  the  external  pterygoid  muscle. 

The  internal  lateral  ligament  is  a  thin,  fibrous  band  which  lies  beneath  the 
inferior  dental  vessels  and  nerve  ;  it  passes,  with  the  lingual  and  inferior  dental 
nerves,  through  the  triangular  interval  between  the  two  pterygoid  muscles  and  the 
incised  edge  of  the  jaw. 

The  external  pterygoid  muscle,  the  more  superficial  of  the  two  pterygoids, 
arises  by  an  upper  head  from  that  portion  of  the  greater  wing  of  the  sphenoid 
bone  situated  between  the  pterygoid  ridge  and  the  foramina  ovale  and  spinosum ; 
by  a  lower  head  from  the  outer  surface  of  the  external  pterygoid  ]ilate  of  the 
sphenoid  Ijone,  from  the  tuberosities  of  the  palate  and  superior  maxillary  bones. 
Its  fibers  pass  horizontally  backward  and  converge  for  insertion  into  the  inter- 
articular  fibro-cartilage  of  the  temporo-maxillary  joint  superiorly,  and  inferiorly 
into  the  anterior  portion  of  the  inner  surface  of  the  neck  of  the  inferior  maxilla. 


680  SURGICAL  ANATOMY. 

It  is  related,  externally,  with  the  ramus  of  the  inferior  maxilla,  the  temporal 
and  masseter  muscles,  the  superficial  ])ortion  of  the  internal  pterygoid  muscle,  the 
internal  maxillary  artery,  the  anterior  and  posterior  deep  temporal  arteries,  and 
the  buccal  artery  and  nerve.  Internally,  it  is  in  relation  with  the  deep  part  of  the 
internal  pterygoid  muscle,  the  middle  meningeal  artery,  and  the  inferior  maxillary 
nerve,  the  internal  lateral  ligament  of  the  lower  jaw,  the  lingual  and  inferior  dental 
nerves,  which  emerge  from  beneath  its  lower  border ;  the  long  buccal  nerve,  which 
runs  between  its  two  heads ;  the  chorda  tympani  nerve,  and  the  anterior  and 
posterior  deep  temporal  and  masseteric  nerves,  which  pass  out  from  beneath  the 
upper  border  of  the  muscle. 

Blood  Supply. — From  the  external  pterygoid  branches  of  the  internal  maxil- 
lary artery. 

Nerve  Supply. — From  the  inferior  maxillary  nerve. 

Action. — Tlie  external  laterygoid  muscles  acting  together  pull  the  lower  jaw 
forward  ;  alternately,  they  move  it  forward  and  laterally ;  and,  singly,  forward  and 
to  the  opposite  side.     They  are  muscles  of  trituration. 

The  internal  pterygoid  muscle  (the  internal  masseter)  arises  by  two  heads,  a 
superficial  and  a  deep.  The  superficial,  the  smaller,  arises  from  the  lower  and 
back  part  of  the  tuberosity  of  the  upper  jaw,  and  the  outer  side  of  the  tuberosity  of 
tlie  palate  bone.  The  deep  lies  beliind  the  lower  head  of  the  external  pterygoid 
and  arises  from  the  internal  surface  of  the  external  pterygoid  plate,  and  from  the 
grooved  portion  of  the  tuberosity  of  the  palate  bone  situated  in  the  pterygoid  fossa. 
These  two  heads  unite  at  the  lower  margin  of  the  external  pterygoid  muscle,  and 
thence  extend  downward,  backward,  and  outward  for  insertion  into  the  rough  irtner 
surfiice  of  the  pcsterior  portion  of  the  ramus  of  the  lower  jaw  included  between 
the  angle  and  the  inferior  dental  foramen. 

It  is  related,  externally,  with  the  ramus  of  the  lower  jaw,  the  external 
pterygoid  muscle,  the  internal  lateral  ligament  of  the  lower  jaw,  the  lingual  or 
gustatory  nerve,  and  inferior  dental  and  mylo-hyoid  vessels  and  nerves ;  internally, 
with  the  tensor  palati,  stylo-glossus,  stylo-hyoid,  posterior  belly  of  the  digastric, 
and  tlie  superior  constrictor  muscle  of  the  pharynx. 

Blood  Supply. — From  the  mylo-hyoid  and  internal  pterygoid  branches  of  the 
internal  maxillary  artery. 

Nerve  Supply. — From  the  internal  pterygoid  branch  of  the  inferior  maxillary 
nerve. 

Action. — Both  internal  pterygoid  muscles  acting  together  draw  the  lower  jaw 
upward  and  fovAvard  ;  and,  singly,  u])ward  and  to  the  oppo.site  side. 

The  internal  maxillary  artery,  the  larger  of  the  two  terminal  branches  of 
the  external  carotid,  arises  in  the  parotid  gland,  opposite  to  or  slightly  lower  than 


S— 44 


PLATE  CLXIX, 


Infraorbital  a. 


Orbital  b 


Palpebral  b 

Anterior  dental  br. 
Nasal  br.- 
Labial  br. 
Posterior  dental  a 


Gingival  br.of  posterior  dental  a 


Spheno-palatine  a. 

Pterygo-palatine  a. 
/Vidian  a. 


Decending  palatine  a. 

Anterior  deep  temporal  a 
External  pterygoid  a. 

Posterior  deep  temporal  a. 
Small  meningeal  a. 
Middle  meningeal  a. 
Superficial  temporal 

Typanic  a. 
Deep  auricular  a. 
nternal  maxillary  a 

External  carotid  a 


Mylo-hyoid  a. 
Submental  a. 
Mental  a. 
Incisive  br. 


Masseteric  a. 


Internal  pterygoid  a. 
nferior  dental  a. 


Buccal  a. 


ETERNAL   MAXILLAKY  AKILRY  AND   BRANCHES. 
()82 


FACE.  683 

the  neck  of  tho  lower  jaw.  The  artorv  is  divided  into  tlirce  portions :  maxillary, 
pterygoid,  and  spheno-niaxillary.  The  Jirsf  or  maxillary  porlion  passes  forward 
between  the  internal  lateral  ligament  and  tlu>  neek  of  tho  lower  jaw,  and  reaches 
the  lower  margin  of  tho  external  pterygoid  nuiscle.  The  second  or  pterygoid  portion 
extends  obliquely  upward  and  forward  upon  the  outer  surface  of  the  external 
pterj'goid  muscle,  and  is  hidden  by  tiie  insertion  of  the  temporal  muscle.  The 
third  or  spheno-maxillary  portion  lies  in  the  spheno-maxillary  fos.sa.  In  some 
instances  the  second  or  pterygoid  portion  runs  entirely  beneath  the  external 
pterygoid  muscle,  but,  by  jiassing  between  the  two  heads  of  that  muscle, 
appears  upon  the  outer  surface  of  the  muscle  just  before  entering  the  spheno- 
maxillary fossa. 

The  branches  of  the  first  or  maxillary  portion  of  the  internal  maxillary  artery 
are :  The  deep  auricular,  tympanic,  middle  meningeal,  small  meningeal,  and 
inferior  dental  arteries. 

The  deep  auricular  artery  pierces  the  wall  of  the  external  auditory  canal  to 
supply  the  tj'mpanic  membrane. 

The  tympanic  artery  passes  behind  the  temporo-maxillary  joint  through  the 
Glaserian  fissure  to  supply  the  tympaimm. 

The  middle  meningeal  artery  runs  upward  between  the  two  roots  of  the 
auriculo-temporal  nerve  to  the  foramen  spinosum,  through  which  it  enters  the 
cranial  cavity  to  supply  the  cranium  and  dura  mater. 

The  sinall  meningeal  artery  ascends  to  the  foramen  ovale,  through  which,  after 
supplying  a  twig  to  the  nasal  fossa  and  soft  palate,  it  enters  the  cranial  cavity. 

The  inferior  dental  artery,  with  its  vcnaj  comites,  accompanies  the  inferior 
dental  nerve  and  passes  downward,  upon  the  internal  pterygoid  muscle  and  the 
internal  lateral  ligament,  entering  the  inferior  dental  foramen  together  with  the 
inferior  dental  nerve.  The  artery  then  occupies  the  inferior  dental  canal,  dis- 
tributing branches  to  the  teeth  ;  it  supplies  an  incisive  branch,  and  emerges, 
on  the  face,  from  the  mental  foramen;  it  is  then  called  the  mental  artery;  the 
mental  arterj'  is  accompanied  l)v  the  mental  nerve,  and  is  distributed  to  the 
structures  of  the  chin  and  lower  lip.  Before  entering  the  inferior  dental  canal 
the  inferior  dental  artery  gives  off  the  mylo-hyoid  artery,  which  accompanies 
the  mylo-hyoid  nerve. 

The  branches  of  the  second  or  pterygoid  portion  are  the  anterior  and  posterior 
deep  temporal,  internal  and  external  pterygoid,  and  the  masseteric  and  buccal 
arteries. 

The  anterior  and  posterior  deep  temporal  arteries  pass  upward  through  the 
corresponding  parts  of  the  temporal  fossa,  between  the  temporal  muscle  and  the 
pericranium,  which  they  supply. 


684  SURGICAL  ANATOMY. 

The  pterygoid  arteries,  varying  in  number,  supply  the  external  and  internal 
pterygoid  muscles. 

The  masseteric  artery,  with  the  masseteric  nerve,  passes  outward  behind  the 
temporal  muscle  through  the  sigmoid  notch  of  the  lower  jaw  to  the  masseter 
muscle. 

The  buccal  artery  accompanies  the  long  buccal  nerve  in  its  forward  course 
between  the  ramus  of  the  lower  jaw  and  the  external  i^terygoid  to  the  buccinator 
muscle. 

The  branches  of  the  third  or  splicno-maxillary  j)ortion  are  the  alveolar,  infra- 
orbital, posterior  or  descending  palatine,  Vidian,  pterygo-palatine,  and  naso- 
palatine or  spheno-palatine  arteries. 

The  alveolar  [posterior  superior  dental  or  posterior  dental)  artery  gives  off 
branches  to  the  gums  and  the  buccinator  muscle,  enters  the  superior  maxilla  at 
its  zygomatic  surface,  and  supplies  the  molar  and  bicuspid  teeth  and  the  mucous 
lining  of  the  maxillary  sinus  or  antrum  of  Highmore. 

The  infra-orbital  artery  immediately  enters  the  infra-orbital  groove  and  canal, 
accompanied  by  the  superior  maxillary  division  of  the  fifth  pair  of  cranial  nerves, 
and  eventually  emerges  upon  the  face  in  company  with  the  infra-orbital  nerve  at 
the  infra-orbital  foramen.  It  supplies  branches  to  the  orbit,  and  gives  off  an 
anterior  superior  dental  branch,  which  runs  downward  in  the  anterior  wall  of  the 
maxillary  sinus  and  supplies  the  incisor  and  bicuspid  teeth  and  the  mucous 
membrane  of  the  maxillary  sinus. 

The  posterior  or  descending  palatine  artery  accompanies  the  posterior  palatine 
branches  of  Meckel's  or  the  spheno-palatine  ganglion  of  the  fifth  pair  of  cranial 
nerves,  through  the  posterior  palatine  canal,  then  emerges  from  the  posterior 
palatine  foramen,  and  passes  forward  in  a  groove  situated  near  the  alveolar  process 
along  the  under  surface  of  the  hard  palate  ;  it  next  enters  the  foramen  of  Stenson, 
a  subdivision  of  the  anterior  palatine  foramen,  and  anastomoses  with  the  naso- 
palatine artery.  It  is  distributed  to  the  hard  and  soft  palate,  palatine  glands,  and 
gums. 

The  Vidian  artery  runs  backward  with  the  "\^idian  nerve  through  the  Vidian 
canal  to  supply  the  uppermost  part  of  the  pharynx,  the  Eustachian  tube,  and  the 
tympanum. 

The  pterygo-palatine  artery,  which  is  very  small,  passes  Ijackward  witli  the 
pharyngeal  nerve  through  tlie  ])tery go-palatine  canal  to  supply  the  upper  pharynx, 
the  sphenoid  cells,  and  the  Eustachian  tube. 

The  naso-palatine  or  spheno-palatine,  the  terminal  artery,  runs  inward  through 
the  naso-palatine  or  spheno-palatine  foramen  into  the  superior  meatus  of  the  nose. 
It  crosses  the  roof  of  this  meatus  between  the  mucous  membrane  and  the  bone  to 


PLATE  CLXX, 


al  temporal  a. 

riculo-temporal  n. 


Anterior  deep  temporal  a 
Anterior  temporal  n 

Orbital  n. 

Superior  maxillary  n.. 

Meckel's  ganglion- 

Infraorbital  a.- 

Posterior  superior  dental  n 

Posterior  temporal  n 

Long  buccal  n 

Chorda  tympani  n 

Lingual  n 

Internal  lateral  ligament 

of  lower  ja 

Buccinator  m.- 
Inferior  dental  n 

Inferior  dental  a 


INFERIOR   MAXILLARY   NERVE. 
686 


FACE.  687 

roai'h  the  se[)tuiu  of  llio  nose,  runs  dowiiwaril  and  forward  in  a  groove  on  the 
vomer,  to  anastomose  with  tlie  posterior  i)aiatine  artery.  Two  or  three  external 
l)ranelies  are  distributed  to  the  mucous  lining  of  the  lateral  nasal  walls,  the  antrum 
of  Highmore  and  the  ethmoid  and  sphenoid  cells. 

Tlie  veins  of  the  pterygo-maxilhny  region  accompany  the  branches  of  the 
internal  maxillary  artery,  and  converge  toward  the  external  pterygoid  muscle, 
aniund  wbicli  they  form  a  di'nse  jilexus — the  pterygoid  plexus.  This  is  drained 
fnmi  its  posterior  part  by  a  short  venous  trunk,  called  the  internal  maxillary  vein, 
wliicii  accompanies  the  first  (maxillary)  portion  of  tlie  internal  maxillary  artery 
into  the  substance  of  the  parotid  gland.  The  internal  maxillary  vein  joins  the 
temporal  vein  to  form  the  temporo-maxillary  vein.  The  pterj-goid  plexus  sends 
a  branch  (anterior  maxillary  or  deep  facial  vein)  from  its  anterior  part  over  the 
buccinator  muscle  to  the  facial  vein.  It  also  communicates  with  the  cavernous 
sinus  by  means  of  a  small  emissary  vein  which  passes  through  the  foramen 
Vesalii  in  tlie  sphenoid  bone. 

The  lymphatics  of  this  region  accompany  the  blood-vessels,  and  are  derived 
from  the  regions  which  those  vessels  supply  and  drain.  They  empty  into  the  deep 
cervical  glands. 

The  nerves  of  the  pterygo-maxillary  region  are  the  inferior  maxillary  division 
of  the  fifth  nerve  and  some  of  its  branches  and  the  chorda  tympani  nerve. 

The  inferior  maxillary  nerve  leaves  the  cranial  cavity  through  the  foramen  ovale. 
It  emerges  fi'om  the  skull  as  a  thick  trunk,  which  lies  external  to  the  Eustachian 
tube  aird  beneath  the  external  pter^'goid  muscle.  It  differs  from  the  other  two 
divisions  of  the  fifth  nerve — the  ophthalmic  and  the  superior  maxillary — in  lieing 
composed  of  both  motor  and  sensory  fibers.  After  leaving  the  skull  it  divides  into 
two  portions,  an  anterior  and  a  posterior.  From  the  anterior  portion,  chiefly  motor, 
are  derived  the  anterior  and  posterior  deep  temporal  nerves,  the  masseteric  nerve, 
branches  to  the  pterygoid  muscles,  and  the  long  buccal  nerve.  The  posterior  divi- 
sion, chiefly  sensory,  divides  into  three  large  branches:  the  auriculo-temporal,  the 
lingual  (gustatory),  and  the  inferior  dental  nerve. 

The  deep  temporal  nerves,  anterior  and  posterior,  arise  from  the  motor  root 
of  the  fifth  nerve,  and  ascend  between  the  perici'anium  and  the  temporal  muscle, 
which  muscle  they  supply. 

The  masseteric  nerve  emerges  from  between  the  external  pterj'goid  muscle 
and  the  pterygoid  ridge.  It  proceeds  backward  along  the  upper  border  of  the 
external  pterj'goid  muscle ;  outward  in  front  of  the  temporo-maxillarj'  articulation, 
and  through  the  sigmoid  notch  of  the  lower  jaw,  together  with  the  masseteric  artery, 
entering  the  niasseter  muscle,  which  it  supplies. 

The  branch  to  the  internal  pterygoid  muscle  arises  from  the  inferior  maxil- 


688  SURGICAL  ANATOMY. 

lary  nerve  before  it  divides  ;  it  gives  off  a  l)ranch  to  the  otic  ganglion,  and  enters 
the  deep  surface  of  the  muscle.  The  branch  to  the  external  pterygoid  muscle  is, 
usually',  a  twig  of  the  long  buccal  nerve,  and  divides  into  two  luanchcs,  which 
enter  the  deep  surface  of  the  muscle. 

The  long  buccal,  a  sensory  nerve,  is  derived  from  the  anterior  portion .  of  the 
inferior  maxillary  division  of  the  fifth  nerve.  It  runs  between  the  two  heads  of 
the  external  pterygoid  muscle,  and  passes  downward  and  forwai-d  lieneath  the 
temporal  muscle  and  the  anterior  edge  of  the  masseter  to  the  buccinator  muscle, 
upon  the  outer  side  of  which  it  communicates  with  the  facial  nerve  and  forms  a 
plexus  from  which  filaments  pass  to  the  adjacent  mucous  membrane  and  skin  of 
the  cheek.  It  contains  all  of  the  sensory  fibers  of  the  anterior  division  of  the 
inferior  maxillary  nerve,  and  a  few  fibers  from  the  motor  root  of  the  fifth  nerve. 
The  motor  fibers  run  to  the  external  pterygoid  and  temporal  muscles. 

The  auriculo-temporal  nerve  arises  by  two  roots,  between  which  pas.ses  the 
middle  meningeal  artery.  It  runs  backward  and  outward  beneath  the  external 
pterj'goid  muscle,  between  the  internal  lateral  ligament  and  the  temporo-maxillarj'^ 
joint,  curves  outward  around  the  neck  of  the  cond3'le  of  the  lower  jaw,  and  pierces 
the  upper  part  of  tlie  parotid  gland.  It  next  ascends  over  the  root  of  the  zygoma, 
in  front  of  the  external  auditory  meatus  and  beneath  the  temporal  arterj'.  In  its 
course  it  receives  communicating  twigs  from  the  otic  ganglion,  and  supplies 
branches  to  the  external  auditory  meatus,  the  parotid  gland,  and  the  temporo- 
maxillary  articulation.  From  the  parotid  gland  it  sends  a  communicating  branch 
to  the  temporo-facial  division  of  the  facial  nerve.  It  divides  near  the  level  of  the 
tragus  into  the  anterior  auricular  and  superficial  temporal  branches.  The  anterior 
auricular  supplies  the  upper  part  of  the  pinna.  The  superficial  temporal  lies  on 
the  outer  side  of  the  superficial  temporal  vessels,  divides,  and  accompanies  the 
anterior  and  posterior  temporal  arteries. 

The  lingual  (gustatory)  nerve  emerges  from  beneath  the  lower  edge  of  the 
external  pterygoid  muscle,  whence  it  descends  internal  to  the  inferior  dental  nerve 
between  the  lower  jaw  and  the  internal  pterygoid  muscle;  thence  it  runs  licnoath 
the  mylo-hyoid  nerve  and  over  the  superior  constrictor  of  the  pharynx,  the  stylo- 
glossus, hyo-glos.sus,  Wharton's  duct,  and  gcnio-hyo-glossus  muscle,  to  the  tip  of 
the  tongue.  On  the  hyo-glossus  muscle  it  is  connected  with  the  submaxillary 
ganglion,  which  will  be  described  with  the  submaxillary  triangle  of  the  neck.  It 
lies  above  the  ganglion  and  Wharton's  duct,  which  it  crosses  at  the  anterior  border 
of  the  hyo-glossus  muscle,  M'here  it  supplies  a  branch  to  the  sublingual  gland  and 
a  communicating  l)ranch  to  the  hyjio-glossal  nerve.  Before  it  emerges  from  behind 
the  external  pterygoid  muscle  it  is  joined  by  the  chorda  tympani  nerve. 

The  lingual  nerve  supplies  branches  to  the  hypo-glossal  nerve,  submaxillary 


PLATE  CLXXI, 


Nasal  n. 


Olfactory  n. 

Olfactory  tract 


Superior  nasal  nerves 
Spheno-palatine  n. 


Meckel's  ganglion 
Vidian  n. 
Pharyngeal  n. 

Nasopalatine  n. 


tiaso-palatine  n 


Interior  nasal  nerves 

Great  palatine  nl 
External  palatine  n. 

Posterior  palatine  n! 

Tensor  palati  m'. 
Internal  pterygoid  m. 

Otic  ganglion 
Sympathetic  root  of  otic  gang'. 

Middle  meningeal  a. 
Auriculo-temporal  n.' 


OLFACTORY  NERVES  AND   INTERNAL  VIEW  OF  THE  SPHEf 

690 


-PALATINE  AND  OTIC   GANGLIA. 


FAVK.  691 

jj;an<j;lit)ii,  mucous  monilmino  of  tlic  iiiuulli,  n;iniis,  suhlin^ual  ^iniul,  ami  lingual 
liraiu'lics  til  lilt."  iiapilhi'  cm  (lie  siilos  ami  lip  of  the  tuiii^nic.  As  the  liii},mal 
nerve  supplies  the  tongiu'  with  (■(unnion  sensation,  the  ]>ain  ihu'  to  neuralj^ia  or 
cancer  of  the  tongue  may  he  relieved  by  division  of  this  nerve.  The  incision 
should  be  made  through  the  mucous  membrane  of  the  floor  of  the  mouth  opposite 
the  second  molar  tooth  of  the  lower  jaw  and  close  to  the  gum,  where  the  nerve  lies 
innnediately  heiH'ath  the  mucous  memlirane. 

The  inferior  dental  nerve,  the  largest  branch  of  the  inferior  maxillary, 
emerges  from  beneath  the  lower  heail  of  the  external  pterygoid  muscle  and  de- 
scends between  the  internal  lateral  ligament  and  the  ramus  of  the  lower  jaw  to 
enter  the  inferior  dental  canal.  At  its  origin  it  lies  internal  to  the  inferior  dental 
artery,  which  it  crosses  at  the  inferior  dental  foramen  ;  the  artery  is,  therefore, 
nearer  the  teeth  than  the  nerve.  It  is  a  sensory  motor  nerve,  Ij'ing  external  to  the 
lingvial  nerve  and  more  sn]ierficial,  the  motor  filaments  being  given  off  as  the 
mylo-hyoid  nerve  just  jirevious  to  its  entrance  into  the  inferior  dental  canal. 

The  mylo-hyoid  nerve  is  accompanied  by  the  mylo-hyoid  artery,  pierces  the 
internal  lateral  ligament  of  the  lower  jaw,  and  descends  to  the  mylo-hyoid  groove 
upon  the  inner  surface  of  the  lower  jaw.  It  then  runs  over  the  superficial  surface 
of  the  mylo-hyoid  muscle,  sujtplying  it  and  the  anterior  belly  of  the  digastric 
muscle.  In  tlie  inferiiir  dental  eanal  the  inferior  dental  nerve  supplies  branches  to 
tlie  molar  and  bicuspid  teeth  and  to  the  gums,  and  divides  into  an  incisive  and  a 
mental  branch  opposite  the  mental  foramen. 

The  incisive  branch  passes  forward  and  inward  in  the  inferior  dental  canal 
to  supply  the  canine  and  incisor  teeth  and  the  adjacent  region  of  the  gum. 

The  mental  branch  emerges  ujion  the  face  at  the  mental  foramen,  and  after 
commimicating  with  the  supra-maxillary  branch  of  the  facial  nerve  divides  into 
several  branches.  These  supply  the  mucous  membrane  of  the  lower  lip  and  the 
fascia  and  skin  of  the  lip  and  chin. 

The  chorda  tympani  nerve  arises  from  the  facial  in  the  aqueductus  Fallopii, 
almost  one-fourth  of  an  inch  above  the  stylo-mastoid  foramen.  It  runs  in  the 
iter  chorda;  posterius  to  the  middle  ear,  where  it  passes  between  the  hamlle  of  the 
malleus  and  the  fibrous  layer  of  the  membrana  tympani  externally,  and  the 
mucous  membrane  internally.  It  next  enters  the  iter  chordre  anterius,  or  canal 
of  Huguier,  to  reach  the  pterygo-maxillary  region,  where  it  joins  the  outer  side 
of  the  lingual  nerve  beneath  the  external  pterygoid  muscle.  Some  of  its 
Hbers  leave  tlie  lingual  nerve  to  enter  the  submaxillary  ganglion  and  sublingual 
gland. 

The  otic  (Arnold's)  ganglion  lies  upon  the  internal  surface  of  the  trunk 
of  the   inferior  maxillarv  division    of    the  fifth  nerve,    in    front   of    the    middle 


692  SURGICAL  ANATOMY. 

meningeal  artery,  and  may  be  found  by  tracing  any  of  the  larger  branches  of 
the  nerve  until  the  root  of  the  parent  stem,  near  the  foramen  ovale,  is  reached. 
Its  sj'Uipathetic  root  is  derived  from  the  j^lexus  on  the  middle  meningeal  artery  ; 
its  sensory  root  from  the  inferior  maxillary  through  the  internal  pterygoid  nerve ; 
its  motor  root  from  the  small  superficial  petrosal  nerve,  which  communicates 
with  the  tympanic  branch  of  the  glosso-pharyngeal  nerve.  It  communicates 
with  the  auriculo-temporal  and  chorda  tympani  nerves.  ^lotor  fibers  of  the 
inferior  maxillary  nerve  pass  through  it  to  the  tensor  palati  and  tensor  tympani 
muscles. 

Dissection. — To  study  the  first  portion  of  tlie  internal  maxillary  arterj'  and 
its  branches,  the  trunk  of  the  inferior  maxillary  nerA-e,  tlie  origins  of  its  branches, 
and  the  otic  ganglion,  it  is  necessary  to  remove  the  external  pterygoid  muscle, 
the  condyle  of  the  jaw,  and  the  remainder  of  the  ramus  as  far  as  the  transverse 
incision  in  the  ramus. 

Fracture  of  the  base  of  the  skull  may  cause  serious  hemorrhage  into  the 
pterygo-maxillary  region,  because  of  rupture  of  the  meningeal  vessels.  Lacerations 
of  the  deep  temporal  vessels  due  to  cranial  fracture  would  result  in  the  effusion  of 
blood  into  this  space,  its  escape  above  the  zygoma  being  rendered  impossible 
because  of  the  attachments  of  the  temporal  fascia.  Under  these  conditions  pain  on 
jiressure  made  below  the  zygoma  and  behind  the  malar  bone  would  be  a  rational 
symptom.  Such  eff'usion  might  give  rise  to  secondary  irritation  of  the  nerves 
in  this  space.  Thus,  irritation  of  the  chorda  tympani  nen'e  would  cause  sali- 
vation ;  of  the  lingual,  disturbances  of  sensation  and  taste  at  tlie  end  of  the 
tongue ;  of  the  inferior  dental,  toothache  ;  of  the  motor  branches,  tonic  or  clonic 
spasms  of  the  muscles  of  mastication  ;  of  the  niylo-hyoid  and  anterior  bellj'  of  the 
digastric  muscles,  more  or  less  complete  fixation  of  the  jaw. 

Tumors  and  abscess  would  have  similar  effects,  but  would  vary  in  degree  in 
accordance  with  the  exact  location  and  rapidity  of  growth.  Owing  to  the  presence 
of  imjwrtant  structures  in  this  space,  it  is  well  to  practise  Hilton's  method  of 
opening  a  deep  abscess  in  this  region  ;  this  is  done  as  follows :  Tlirough  an 
incision  in  the  skin  push  a  grooved  director  into  the  abscess ;  then  insert  a  jmir 
of  forceps  along  the  director,  and  withdraw  them  with  the  blades  sufl[icient]y 
separated  to  make  an  opening  large  enough  to  insure  good  drainage.  It  is  im- 
possible to  do  serious  damage  by  this  procedure. 

Dissection. — The  pterygo-maxillary  region  sliould  now  be  thoroughly 
cleaned,  in  order  to  study  the  spheno-maxillary  fissure,  the  pterygo-maxillary 
fissure,  and  tlie  spheno-maxillary  fossa. 

It  will  be  remend^ered  that  tlie  zygomatic  fo.ssa  was  mentioned  in  connection 
with  the  contents  of  the  pterygo-maxillary  region  ;  its  contents  have  been  dissected. 


FACE.  693 

They  consist  of  the  lower  part  of  tlic  tiiuiMiral  muscle,  tlie  internal  and  exlt^rnal 
pterygoid  nm^cles,  the  internal  maxillary  artery,  the  inferior  maxillary  nerve, 
branches  of  the  artery  and  nerve,  ami  the  chorda  tympani  nerve. 

The  zygomatic  fossa  practically  corresponds  to  the  upper  portion  of  the 
pterygo-maxillary  region.  It  is  hoinided  above  by  the  under  surface  of  the  great 
wing  of  the  sphenoid  and  adjacent  portion  of  the  temporal  bone  ;  in  front,  by  the 
zygomatic  surface  of  the  superior  maxilla  ;  behind,  by  the  posterior  border  of  the 
pterygoid  process  of  the  sphenoid  bone  and  the  erainentia  articularis ;  internally, 
by  the  external  pterygoid  plate  ;  and  externally,  by  the  pterygoid  ridge,  the  zygo- 
matic arch,  and  the  ramus  of  the  inferior  maxilla.  At  the  upper  and  inner  part  of 
the  zygomatic  fossa  two  fissures  will  be  ob.served,  one  horizontal,  the  other  vertical. 
The  horizontal  fissure  is  the  spheno-maxillary,  which  opens  into  the  outer  and  back 
part  of  the  orbit.  It  transmits  the  infra-orbital  artery  and  vein,  branches  from 
Meckel's  ganglion,  and  the  superior  maxillarj^  nerve  and  its  orbital  branch.  Its 
bony  walls  are  formed,  above,  by  the  lower  border  of  the  orbital  surface  of  the  great 
wing  of  the  sphenoid  ;  below,  by  the  orbital  surface  of  the  superior  maxilla  and  a 
portion  of  the  palate  bone ;  externally,  by  a  small  part  of  the  malar  bone.  It  joins 
the  pterygo-maxillary  fissure  at  a  right  angle.  The  vertical  fissure  is  the  pterygo- 
maxillary,  which  is  formed  by  the  angle  between  the  superior  maxillary  bone  and 
the  pterygoid  process  of  the  sphenoid  bone.  It  transmits  the  internal  maxillary 
artery. 

The  spheno-maxillary  fossa  lies  below  the  great  wing  of  the  sphenoid, 
external  to  the  vertical  portion  of  the  palate  bone,  and  between  the  orbital  process 
of  the  palate  bone  and  the  zygomatic  surface  of  the  superior  maxilla,  in  front,  an<l 
the  pterygoid  process,  behind.  It  contains  the  terminal  portion  of  the  internal 
maxillary  artery,  the  branches  of  this  portion,  the  sujjerior  maxillary  nerve,  and 
Meckel's  ganglion.  Three  foramina  are  found  in  the  posterior  wall :  the  foramen 
rotundum,  which  transmits  the  superior  maxillary  division  of  the  fifth  nerve  ;  below 
this,  the  anterior  opening  of  the  \'idian  canal,  which  transmits  tlie  ^'idian  nerve 
and  vessels,  and  still  lower  the  ptcrygo-pdlatinc  forawni — the  anterior  opening  of 
the  pterygo-palatine  canal,  which  transmits  the  pterygo-palatine  vessels  and  the 
pharyngeal  nerve.  On  the  internal  wall  is  the  sphe7}0-pa!atine  foramen,  which 
transmits  the  spheno-palatine  vessels  and  the  naso-palatine  nerve.  Below  the 
spheno-palatine  foramen  is  the  orifice  of  the  posterior  palatine  canal,  which  trans- 
mits the  posterior  or  descending  palatine  vessels  and  nerve. 

The  superior  maxillary  (second  division  of  the  fifth)  nerve  is  a  sensory 
nerve.  It  arises  from  the  Gasserian  ganglion  at  the  apex  of  the  petrous  portion 
of  the  temporal  bone,  pas.ses  through  the  foramen  rotnnduin  into  the  spheno- 
maxillary fossa,  and  enters  the  infra-orbital  canal  \nth  the  infra-orbital  artery  to 


694  SURGICAL  ANATOAfY. 

become  the  infra-orbital  nerve.  Its  branches  are  :  In  the  cranial  cavity,  recurrent 
twigs  to  the  dura  mater,  which  communicate  with  branches  of  the  inferior  maxillary 
nerve;  in  the  spheno-maxillary  fossa,  orbital  or  tempovo-malar,  spheno-j)alatine,  and 
posterior  superior  dental  branches;  in  the  infra-orbital  canal,  middle  superior  dental 
and  anterior  superior  dental  nerves;  and  upon  the  face,  the  terminal  divisions  of  the 
infra-orbital  nerve,  the  palpebral,  nasal,  and  labial  branches.  In  the  spheno- 
maxillary fossa  Meckel's  ganglion  is  associated  with  it. 

Dissection. — Remove  the  outer  wall  of  the  orbit  and  that  portion  of  the 
greater  wing  of  the  sphenoid  bone  external  to  the  foramen  rotundum  b}'  sawing 
downward  from  the  incised  edge  of  the  skull  made  in  removing  the  brain.  The 
saw  should  pass  through  the  outer  part  of  the  sphenoid  fissure  and  external  to  the 
foramen  rotundum. 

The  orbital  or  temporo-malar  nerve  enters  the  orbit  through  the  spheno- 
maxillary fissure.  At  the  posterior  part  of  the  orbit  it  divides  into  a  temporal 
and  a  malar  branch.  The  temporal  branch  runs  forward  in  the  periosteum,  lying 
in  a  groove  in  the  bone,  and  passes  through  a  foramen  in  the  malar  bone  (spheno- 
malar  foramen)  to  enter  the  temporal  fossa.  It  runs  upward  lieneath  the  temporal 
muscle,  piercing  it  and  both  lamellre  of  the  temporal  fascia  to  .supply  the  skin  of 
the  temporal  region  ;  it  pierces  the  superficial  layer  of  the  temporal  fascia  about 
an  inch  above  the  zygoma.  In  the  orbit  it  communicates  with  the  lacrj'mal 
nerve ;  and  in  the  temporal  region  with  the  temporal  l^ranch  of  the  facial  nerve. 
The  malar  branch  (ramus  .subcutaneus  malae)  runs  forward  along  the  external  and 
inferior  jiortion  of  the  orbit,  passes  through  the  malar  foramen,  pierces  the  orbicu- 
laris palpebrarum,  and  suj)plies  the  skin  of  the  cheek.  It  communicates  with 
the  malar  branch  of  the  facial  nerve  and  with  the  pal2:iebral  branches  of  the  infra- 
orbital nerve. 

The  spheno-palatine  branches  are  two  twigs  -which  descend  to  Meckel's 
ganglion  from  its  sensoiy  root. 

The  posterior  superior  dental  nerves  are,  usually,  two  in  number,  and  arise 
from  the  superior  maxillary  nerve  as  it  enters  the  infra-orbital  canal.  They  pass 
downward  and  enter  the  foramina  in  the  zj'gomatic  surface  of  the  superior  maxilla  ; 
tlit y  next  run  forward  in  canals  in  the  outer  M'all  of  the  antrum  of  Highmore 
and  abo\-e  the  roots  of  the  molar  teeth  to  join  the  middle  superior  dental  nerve. 
They  supply  branches  to  the  pulp  of  the  molar  teeth,  to  the  gums,  and  to  the  mucous 
membrane  of  the  antrum  of  Highmore. 

The  middle  superior  dental  nerve  is  given  off  at  the  posterior  part  of  the 
infi'a-orhital  canal,  or  it  may  1h'  a  branch  of  the  anterior  .superior  dental  nerve.  It 
supi)lies  the  bicu.spid  teetii  and  connnunicates  with  the  anterior  superior  and 
posterior  superior  ilnital  nerves. 


PLATE  CLXXII 


Infraorbital  a. 

Infraorbital  n. 

Posterior  superior  dental  n. 
Orbital  n. 

Spheno-palatine  n. 


Middle  sup 

Middle  super! 

Anterior  super! 

Anterior  supetio 

Palpebr; 


Nasal  branches 
Labial  branch 


Gingival  a.. 


ary  n. 
ganglion 


-5th  n.  _  / 


Mental  n 
Mental  a. 


Mylo-hyold  n. 
Chorda  tympani  n. 

Lingual  n. 


SUPERIOR  AND  INFERIOR  MAXILLARY  NERVES. 
695 


FACE.  697 

The  anterior  superior  dental  nerve  is  larger  tlmn  the  other  two  superior 
dental  nerves,  and  arises  posterior  to  the  iufra-orbital  foramen  ;  it  runs  downward 
in  the  anterior  wall  of  the  antrum  of  Ilighmore,  and  supplies  the  incisor  and 
canine  teeth,  and  also  a  liraiuh  to  tlie  nasal  fossa.  The  anterior  and  middle 
superior  dental  nerves  may  be  seen  by  raisirig  the  superior  maxillary  nerve  from 
the  tioor  of  the  infra-orbital  canal. 

The  infra-orbital  nerve  emerges  upon  the  face  at  the  infra-orbital  foramen, 
which  lies  beneath  the  levator  labii  superioris  muscle.  It  divides  here  into  palpe- 
bral, nasal,  and  labial  branches,  which,  with  the  infra-orbital  branch  of  the  facial 
nerve,  form  tlie  infra-orbital  plexus. 

The  palpebral  branches  pierce  the  origin  of  the  levator  labii  superioris  muscle 
and  supply  the  integument  and  conjunctiva  of  the  lower  eyelid. 

The  na.ml  branches  pass  inward  under  the  levator  labii  superioris  ala}que  nasi 
muscle  to  supply  the  skin  of  the  nose. 

The  labial  branches  are  the  largest  and  most  numerous.  Tliey  run  downward 
beneath  the  levator  labii  superioris  muscle  to  supply  the  skin,  mucous  membrane, 
and  other  tissues  of  the  upper  lip. 

Meckel's  or  the  spheno-palatine  ganglion  is  situated  in  thespheno-maxillary 
fossa  below  the  superior  maxillary  nerve.  It  is  triangular  in  shape,  of  a  reddish- 
gray  color,  and  measures  about  one-fifth  of  an  inch  in  its  longest  diameter.  Its 
sensory  root  is  derived  from  the  superior  maxillary  through  the  spheno-palatine 
nerve,  most  of  the  fibers  of  which  do  not  enter  the  ganglion  but  pass  anterior  to  it. 
Its  motor  root  is  derived  from  the  facial  through  the  great  superficial  petrosal 
nerve,  which  assists  the  great  deep  petrosal  in  forming  the  Vidian  nerve.  Its 
sympathetic  root,  the  great  deep  petrosal  nerve,  just  mentioned,  is  derived  from  the 
carotid  plexus.  The  motor  and  sympathetic  roots  enter  the  spheno-maxillary 
fossa  as  the  Vidian  nerve.  Its  branches  are  classified  as  ascending,  descending, 
internal,  and  posterior. 

The  ascending  or  orbital  branches  pass  through  the  spheno-maxillary  fissure, 
and  pierce  the  inner  wall  of  the  orbit  to  supply  the  mucous  membrane  of  the 
sphenoid  sinus  and  posterior  ethmoid  cells. 

The  descending  or  palatine  branches  are  derived  mainly  from  the  spheno- 
palatine branches  of  the  superior  maxillary  nerve.  They  are  divided  into  anterior, 
external,  and  posterior  palatine  nerves. 

The  anterior  or  large  palatine  nerve  passes  downward  in  the  posterior  palatine 
canal  together  with  the  posterior  palatine  arteiy,  and  appears  on  the  hard  palate  at 
the  posterior  palatine  foramen.  It  runs  forward  in  a  groove  on  the  under  surface  of 
the  hard  palate,  and  joins  the  terminal  |)ortion  of  the  naso-palatine  nerve.  It  sup- 
plies the  gums  and  the  muco-periosteum  of  the  hard  palate.     While  in  the  poste- 

S— 45 


698  SURGICAL  ANATOMY. 

rior  palatine  canal  it  gives  off  two  branches  (inferior  nasal  nerves),  -whieli  iiierce 
the  vertical  plate  of  the  palate  bone  to  supply  the  mucous  membrane  of  the  l^ack 
part  of  the  middle  and  inferior  meatuses  and  the  inferior  turl^inated  bone. 

The  external  or  middle  palatine  nerve,  when  present,  is  small  ;  it  descends  in 
the  external  palatine  canal  to  supply  tjhe  tonsil  and  adjacent  mucous  membrane. 

T\ie  posterior  or  small  palatine  nerve  A-escemls  in  the  accessory  palatine  canal 
to  supply  the  tonsil,  adjacent  mucous  membrane,  levator  palati,  and  azygos  uvulae 
muscles.  Witli  the  external  palatine  nerve  it  joins  a  branch  from  the  glosso- 
pharvngeal  nerve  to  form  tlie  circulus  tonsillaris,  a  plexus  around  the  tonsil. 

The  internal  or  nasal  branches  are  derived  partly  from  the  spheno-palatine 
ganglion  and  partly  from  the  spheno-palatine  nerve.  They  are  divided  into  septal 
and  superior  nasal  Ijranches. 

The  septal  hranches  pass  through  the  spheno-palatine  foramen  with  the  naso- 
palatine artery,  and  cross  the  roof  of  the  nasal  fossa  beneath  the  mucous  mem- 
brane and  below  the  opening  of  the  sphenoid  sinus  to  reach  the  septum,  where  the 
smaller  branches  terminate. 

The  naso-pnlatine  nerve  (nerve  of  Cotunnius),  the  largest  of  these  branches, 
runs  downward  and  forward  on  the  septum  of  the  nose,  between  the  periosteum 
and  the  mucous  membrane,  to  the  anterior  palatine  canal,  where  it  passes  through 
one  of  tlie  foramina  of  Scarpa  (subdivisions  of  the  anterior  palatine  foramen)  to 
supply  the  mucous  membrane  of  the  anterior  portion  of  the  hard  palate  and  to 
join  the  terminal  portion  of  the  anterior  palatine  nerve. 

The  superior  nasal  nerves  are  several  twigs  which  pass  through  the  spheno- 
palatine foramen  to  supply  the  mucous  membrane  of  the  posterior  part  of  the 
middle  and  superior  turbinated  bones,  and  of  the  posterior  ethmoid  cells  and 
antrum  of  Higlimore. 

The  posterior  branch  is  tlic  pharyngeal  ner\'e. 

The  pharyngeal  or  pterygo-palatine  nerve  runs  backward  through  the 
pterygo-palatine  canal  in  company  Avith  the  pterygo-palatine  artery ;  it  supplies 
the  ui)per  [lortion  of  tlie  i>harynx  and  the  Eustachian  tube. 

Tlie  Vidian  nerve  lias  licen  considered  a  posterior  branch  of  the  spheno- 
palatine ganglion,  but  it  is  really  the  nerve  which  is  formed  by  the  junction  of  its 
motor  and  sympathetic  roots.  It  will  be  seen  emerging  from  the  Vidian  canal  at 
tlie  root  of  the  pterygoid  process. 

The  superior  maxillary  nerve  and  its  many  communications  are  especially 
important,  because  it  is  .so  frequently  affected  by  neuralgia,  the  operation  for 
which  follows. 

Trifacial  neuralgia  may  be  due  to  many  causes  ;  among  these  are:  Reflected 
irritation  fi'nm  diseased  teeth,  erujition  of  the  wisdom  teeth,  irritable  ulcers  in  the 


FACE.  699 

area  of  distribution  of  the  norvc,  and  abscess  or  tumors  of  the  antrum  of  IIi<,diniore, 
of  the  pterysj;<)-maxillarv  region,  or  of  the  spheno-maxilhiry  fossa.  Tiie  infra-orbital 
foramen  is  on  a  line  drawn  from  tlie  supra-orbital  notch  to  a  point  between  the 
bicuspid  teeth  of  the  upper  jaw.  It  corresponds  to  a  ])oint  about  one-half  (if  an 
inch  below  the  junction  of  the  inner  and  the  middle  one-third  of  the  infra-orbital 
margin.  The  infra-orbital  nerve  is  best  exposed  through  a  .semilunar  incision  with 
its  convexity  directed  downward,  and  carried  a  short  distance  below  the  foramen. 
A  flap,  including  skin,  cellulai:  tissue,  and  the  orbicularis  palpebrarum  muscle,  is 
raised.  The  levator  labii  superioris  muscle,  which  covers  the  foramen,  is  now 
aii])arent,  and  must  lie  displaced  laterally  or  divided,  when  both  the  ini'ra -orbital 
plexus  and  nerve  will  readily  be  found,  surrounded  by  a  small  quantity  of  fatty 
tissue. 

In  some  cases  of  obstinate  neuralgia  of  the  peripheral  branches  of  the  trifacial 
nerve  it  becomes  necessary  to  remove  a  portion  of  the  affected  nerve  in  order 
to  give  the  jiatient  relief  The  infra-orbital  nerve  may  be  divided  at  its  exit  from 
the  infra-orbital  foramen  by  either  a  subcutaneous  or  a  conjunctival  section  ;  in 
the  latter  method  the  tenotome  is  introduced  through  the  conjunctiva  and  carried 
over  the  infra-orbital  margin  ;  it  is  best  to  expose  the  infra-orbital  nerve  by 
turning  up  a  flap  from  the  face,  when  a  portion  of  the  nerve  can  be  removed. 
The  nerve  being  exposed  and  freed  at  its  point  of  exit,  a  slightly  curved  or 
hooked  knife  can  be  entered  close  to  the  external  canthus  just  below  the  outer 
palpebral  ligament,  and  passed  backward  along  the  floor  of  the  orbit  toward 
the  apex,  and  along  the  anterior  border  of  the  spheno-maxillary  fissure,  which 
is  crossed  by  the  nerve  at  about  an  inch  behind  the  orbital  margin.  The 
knife  is  then  carefully  withdrawn,  and  the  nerve  divided  as  it  enters  the  infra- 
orbital canal.  Traction  is  then  made  upon  the  peripheral  end  of  the  nerve  to 
remove  it  from  the  infra-orbital  canal.  Should  the  knife  be  carried  too  far  and  the 
spheno-maxillary  fossa  be  entered,  serious  hemorrhage  would  result. 

The  objections  to  this  last  method  are,  first,  the  hemorrhage  which  results 
from  the  division  of  the  infra-orbital  vessels  inaccessible  for  ligature ;  second,  the 
uncertainty  of  accomplishing  the  division  of  the  nerve  ;  and  third,  in  many  of  these 
cases  the  posterior,  as  well  as  the  anterior,  dental  branches  arc  involved  ;  if  this  be 
the  case,  removal  of  the  superior  maxillary  nerve  behind  Meckel's  ganglion  will  be 
required  in  order  to  insure  positive  relief. 

The  liest  method  for  removing  the  superior  maxillaiy  nerve  through  the  face 
from  behind  Meckel's  ganglion  is  the  following :  Expose  and  free  the  infra-orbital 
ners'e  at  its  exit  from  the  infra-orbital  foramen  ;  then,  with  a  three-quarter-inch 
trephine,  remove  a  button  of  bone  from  the  anterior  wall  of  the  antrum  of  High- 
more  ;  this  button  should  include  the  outer  wall  of  the  infra-orbital  foramen,  and 


700  SURGICAL  ANATOMY. 

in  removing  it  care  must  he  taken  not  to  sever  the  infra-orbital  nerve.  Open  the 
antrum  by  tearing  through  the  Uning  membrane,  and  then,  with  a  trephine  one- 
half  of  an  inch  in  diameter  or  with  a  small  chisel,  perforate  its  posterior  wall. 
This  opens  up  the  spheno-maxillar}'  fossa,  and  w'ill  be  followed  by  considerable 
bleeding  from  wounded  branches  of  the  internal  maxillary  vessels.  Before  pro- 
ceeding with  the  next  step  in  the  operation  pack  the  opening  in  the  posterior  wall 
with  sterile  gauze  to  check  the  hemorrhage ;  then,  with  a  small  chisel,  break  away 
the  floor  of  the  infra-orbital  canal  and  the  back  part  of  the  floor  of  the  orbit  along 
the  roof  of  the  antrum  ;  this  permits  the  infra-orbital  nerve  to  be  drawn  down  into 
the  antrum,  wheU;  b}^  making  slight  traction  upon  it,  a  pair  of  long,  slender  scissors, 
sharply  curved  and  with  blunt  points,  can  be  carried  along  the  nerve  through  the 
antrum,  and  the  superior  maxillary  nerve  divided  behind  Meckel's  ganglion.  In 
breaking  away  the  floor  of  the  infra-orbital  canal  the  infra-orbital  vessels  will  be 
torn,  but  the  bleeding  therefrom  is  of  no  serious  consequence  and  can  be  controlled 
by  packing  a  strip  of  sterile  gauze  into  the  broken  canal.  If  hemorrhage  persist 
after  the  removal  of  the  superior  maxillary  nerve,  the  splieno-maxillary  fossa  also 
may  be  packed  with  gauze,  which  should  protrude  through  the  opening  in  the 
anterior  wall  of  the  antrum.  The  gauze  may  remain  for  two  or  three  days  and 
serves  a  two-fold  purpose  :  in  controlling  the  bleeding  and  in  favoring  drainage. 
The  operation  is  facilitated  by  the  use  of  an  incandescent  lamp  attached  to  a 
head-band. 

Clavus  (nail)  is  the  name  given  to  a  neuralgic  pain,  which,  from  its  intensity 
and  the  smallness  of  its  area,  is  likened  to  a  nail  being  driven  tiirough  the  flesh 
and  bone.     It  generally  affects  hysteric  young  women. 

It  is  not  inappropriate  for  the  author  to  say  here  that,  having  had  a  large 
experience  in  the  operative  treatment  of  cases  of  trigeminal  neuralgia  (tic  doulou- 
reux), he  is  of  the  opinion  that  the  simpler  operative  procedure  should  first  be 
pursued,  for  the  period  of  relief  following  any  operation  is,  comparatively  speak- 
ing, but  temporary  in  the  majority  of  cases.  This  is  not  in  accord  with  the  views 
of  some  of  the  leading  operators,  but  it  has,  nevertheless,  been  the  author's  experi- 
ence. He  has  operated  on  a  number  of  cases  several  times, — in  one  instance  as 
many  as  five, — each  operation  having  been  followed  by  relief  for  from  twelve  to 
eighteen  months.  The  peripheral  operations  may  be  repeated,  a  little  more  of  the 
nerve  being  removed  at  each  operation.  This  course  affords  the  patient  a  more 
prolonged  jioriod  of  relief  tliau  could  l)e  obtained  by  first  performing  the  more 
radical  operation.  As  a  last  resort,  the  most  radical  operation  of  all,  intra-cranial 
section  of  the  affected  nerve  or  removal  of  the  Gasserian  ganglion,  may  be  done. 
In  cases  where  the  neuralgia  has  returned  after  removal  of  the  superior  maxillary 
nerve  back  of  Meckel's  ganglion  by  opening  both  walls  of  the  antrum  and  removing 


FACE.  701 

the  infra-orbital  nerve  from  its  canal,  flie  author  has,  bj'  sinij)!}'  cleaning  out  the 
track  of  the  original  wound,  seen  JvWvi'  foiidw. 

In  trifacial  neuralgia  one,  two,  or  all  three  branches  of  the  trifacial  nerve 
may  be  involved.  The  oiihthahnic  division  supplies  the  skin  above  the  palpebral 
fissure  ;  the  superior  maxillary  division,  the  skin  between  the  palpebral  and  oral 
fissures,  including  the  temple ;  the  inferior  maxillary  division  supplies  the 
skin  below  the  oral  fissure  as  far  as  the  liyoid  bone.  The  superior  and  the 
inferior  maxillary  nerves  also  supply  the  teeth  through  their  branches,  while 
the  latter  supplies  the  anterior  two-thirds  of  the  tongue  through  its  lingual 
branch ;  the  motor  root  of  the  third  division  also  supplies  the  muscles  of 
mastication,  except  the  buccinator — i  e.,  the  temporal,  masseter,  and  external 
and  internal  pterygoid  muscles.  Thus,  complete  paralysis  of  the  trifacial  nerve 
abolishes  sensation  upon  one  side  of  tlie  face  and  on  top  of  the  head,  from 
the  highest  point  of  the  vertex  above  to  the  hyoid  bone  below ;  laterally, 
to  and  including  the  front  of  the  ear  and  external  auditory  canal  and 
temple ;  mesially,  the  anterior  nares  and  the  sensibility  as  to  touch  and  taste  of 
the  anterior  two-thirds  of  the  tongue,  besides  completelj'  paralyzing  the  muscles 
of  mastication  on  the  affected  side,  witli  the  exception  of  th6  buccinator.  Because 
of  the  insensibility  of  the  conjunctiva  the  lids  do  not  properl^y  protect  this  mem- 
brane, and  it  becomes  congested  and  inflamed,  a  condition  which  often  occurs 
spontaneously  through  implication  of  the  troi)hic  fibers  of  the  trifacial  nerve.  At 
the  same  time  anterior  rhinitis  may  result  from  similar  causes,  or  may  be  excited 
by  the  discharge  of  the  conjunctival  secretion  into  the  inferior  meatus  of  the  nose. 

Trifacial  neuralgia  may  be  accompanied  by  active  implication  of  the  trophic 
filaments,  so  that  there  is  not  only  conjunctivitis  and  rhinitis,  ])ut  vesicles  may 
form  upon  the  lips  and  anterior  nares.  This  should  be  borne  in  mind,  as  these 
trophic  nerve  disturbances,  when  overlooked,  may  be  the  source  of  much  per- 
plexity to  the  physician. 

Paralysis  of  the  orbicularis  palpebrarum  muscle  also  leads  to  conjunctivitis, 
from  inability  to  close  the  eyelids ;  this  must  not  be  confounded  with  the  inllani- 
mation  of  perverted  function  of  the  tro]>!iic  nerves. 

The  trophic  filaments  arc  derived  from  the  sympathetic  nerve ;  this  is  a 
general  rule  worth  remembering. 

The  entire  width  of  the  occiput,  as  high  up  as  the  vertex,  and  tlie  l)ack  of  the 
pinna  are  supplied  by  the  occipitalis  major  ners-e.  As  Hilton  pointed  out,  tlie 
pinna  may,  therefore,  often  be  used  to  differentiate  between  spinal  and  cerebral 
central  ner\-e  disease  causing  neuralgia  ;  if  spinal,  the  back  of  the  ])iinia  is  affected 
and  the  front  is  not ;  if  cerebral,  the  signs  are  reversed. 

Reflex  or  referred  pains  are  frequent  in  the  area  of  distribution  of  the  trifacial 


702  SURGICAL  ANATOMY. 

nerve  because  of  the  abundance  of  its  filaments  and  their  numerous  inosculations. 
The  physician  must,  therefore,  be  careful  not  to  be  misled  by  the  location  of  pain, 
for  an  earache  may  be  due  to  a  diseased  tooth,  as  was  the  case  in  a  patient  treated 
by  Hilton  :  Tlie  patient  had  consulted  several  leading  aurists  for  a  persistent 
earache  without  obtaining  relief  except  from  the  use  of  anodynes ;  the  ingenious 
Hilton  sagaciously  concluded  it  to  be  useless  to  treat  where  so  many  others  had 
failed,  and  looked  elsewhere  than  at  the  ear  for  the  cause  of  the  ti-ouble.  This  he 
found  in  a  jagged  molar  tooth  which  was  continually  irritating  a  small  nerve 
filament  at  the  Ijottom  of  an  ulcer  upon  the  side  of  the  tongue  adjoining  the  tooth. 
He  advised  the  removal  of  the  tooth,  which  resulted  in  healing  of  the  ulcer  and 
in  cure  of  the  earache.  In  a  similar  manner  affections  of  any  filament  of  the 
trifacial  nerve  may  produce  pain  in  any  part  supjilied  by  other  branches  of  the 
nerve. 

The  Lymphatic  Glands  of  the  Head  are  divided  into  a  superficial  and  a  deep 
set.  The  superficial  set  is  composed  of  the  occipital,  posterior  auricular,  parotid, 
buccal,  and  submaxillary  lymphatic  glands. 

The  occipital  or  suboccipital  lymphatic  glands  are  situated  in  the  superficial 
fascia  along  the  superior  curved  line  of  the  occipital  bone  over  the  attachments  of 
the  trapezius  muscle  and  the  occipital  belly  of  the  occipito-frontalis  muscle.  These 
glands  receive  the  lymphatic  vessels  from  the  posterior  portion  of  the  scalp  or  that 
area  supplied  by  the  occipital  artery,  and  may  be  involved  in  erysipelas  or  other 
septic  conditions  of  the  posterior  portion  of  the  scalp.  The  efferent  vessels  from 
these  glands  empty  into  the  superficial  lymphatic  glands  of  the  neck. 

The  posterior  auricular  or  mastoid  lymphatic  glands  are  situated  behind  the 
pinna,  over  the  mastoid  process  and  the  insertion  of  the  sterno-mastoid  muscle. 
They  receive  the  lymphatic  vessels  from  the  posterior  auricular  region  and  the 
portion  of  the  scalp  above  it.  Their  efferent  vessels  empty  into  the  superficial 
lymphatic  glands  of  the  neck. 

The  parotid  lymphatic  glands  lie  upon  the  parotid  salivary  gland  in  front  of 
the  pinna,  below  the  zygoma,  and  a  few  are  found  in  the  substance  of  the  parotid 
salivary  gland.  They  receive  the  lymphatic  vessels  from  the  temporal  region,  the 
portion  of  the  scalp  above  it,  and  the  outer  portion  of  the  eyelids  and  of  the  cheek. 
Their  eift'n'nt  vessels  empty  into  the  superficial  lymphatic  glands  of  the  neck  and 
into  the  submaxillary  lymphatic  glands. 

The  buccal  lymphatic  glands  rest  upon  the  buccinator  muscle.  They 
receive  some  of  the  lymjiiiatics  from  the  anterior  portion  of  the  face,  inner  half  of 
the  eyelids,  brow,  and  front  of  the  scalp.  Their  efferent  vessels  empty  into  the 
submaxillary  and  tiic  intiimd  maxillary  lymphatic  glands. 

The   submaxillary    lymphatic    glands    are   the   largest   group.      They   are 


FACE.  703 

situated  below  the  border  of  the  lower  jaw,  ninst  of  tlu'in  lyinn;  in  the  submaxillary 
triangle  in  relation  witli  the  sulimaxillary  salivary  gland  ;  two  or  three  ol'  tlieni 
(supra-hyoid  lyniiiliatics)  lie  above  the  body  of  the  hyoid  bone,  between  the  ante- 
rior bellies  of  the  two  digastric  muscles.  The  submaxillary  lymi)hatic  glands 
receive  the  lymphatic  vessels  from  the  fnint  of  the  scalp,  inner  jiart  of  the 
eyelids,  anterior  portion  of  the  face,  tloor  of  the  nmuth,  anterior  portion  of  the 
tongue,  sul)lingual  and  submaxillary  salivary  glands,  and  some  of  the  ett'erent 
vessels  from  the  parotid  lymphatic  glands.  Their  efferent  vessels  emjity  into  the 
superficial  and  deep  cervical  lymphatic  glands. 

The  deep  lymphatic  glands  of  the  head  are  the  internal  maxillary,  lingual, 
and  post-jiharyngeal  lymphatic  glands. 

The  internal  maxillary  lymphatic  glands  are  situated  in  the  pterygo-maxil- 
lary  region  ;  some  are  in  relation  with  the  internal  maxillary  artery,  others  lie 
upon  the  posterior  portion  of  the  buccinator  muscle,  and  still  other  deep  glands  lie 
upon  tlie  side  of  the  pharynx.  They  receive  the  lymphatic  vessels  from  the  orbi- 
tal, nasal,  temporal,  and  zygomatic  fo.ssa>,  the  roof  of  the  mouth,  and  the  .soft 
palate,  and  some  of  the  efferent  vessels  from  the  buccal  lymphatic  glands.  Their 
efferent  vessels  empty  into  the  deep  cervical  lymphatic  glands  and  partly  into  the 
deep  parotid  lymphatic  glands. 

The  lingual  lymphatic  glands  lie  upon  the  hyo-glossus  and  genio-hyo-glossus 
muscles.  They  receive  the  lymphatic  vessels  from  the  upper  surface  and  posterior 
part  of  the  tongue.  Their  efferent  vessels  unite  with  the  upper  glands  of  the  deep 
cervical  chain. 

The  post-pharyngeal  lymphatic  gland  is  situated  below  the  base  of  the  skull, 
between  the  posterior  wall  of  the  pliarynx  and  the  rectus  capitis  anticus  major 
muscle.  It  receives  the  lymphatic  vessels  from  the  upper  part  of  the  pharynx, 
jRirt  of  the  nasal  fossa,  and  the  upper  part  of  the  prevertebral  muscles. 

The  lymphatic  vessels  of  the  scalp,  which  drain  that  portion  behind  a  ver- 
tical line  passing  through  the  external  auditory  meatus,  terminate  in  the  occipital 
and  posterior  auricular  lymphatic  glands  ;  the  lymphatics  of  the  temporal  region 
of  the  scalp  and  that  portion  above  it  empty  into  the  superficial  and  deep  parotid 
lymphatic  glands ;  the  lymphatic  vessels  of  the  frontal  region  of  the  scalp  follow 
the  frontal,  supra-orbital,  and  the  facial  veins  downward  over  the  face  to  the  sub- 
maxillary lymphatic  glands. 

The  lymphatic  vessels  of  the  face  are  divided  into  a  superficial  and  a  deep 
set.  The  superficial  lymphatics  of  the  anterior  portion  of  the  face — /.  c,  of  the 
inner  half  of  the  eyelids,  of  the  nose,  lips,  and  anterior  part  of  the  cheek — pass 
downward  into  the  submaxillary  lymphatic  glands,  and  those  of  the  outer  half  of 


704  SURGICAL  ANATOMY. 

the  eyelids  and  outer  part  of  tlie  cheek  terminate  in  the  parotid  lymphatic  glands. 
The  deep  lymphatics  of  the  face — i.  e.,  those  of  the  orbit,  part  of  the  nasal  fossa,  the 
hard  and  soft  palates,  deeper  portion  of  the  cheek,  temporal  fossa,  and  pterygo- 
maxillary  region — enter  the  internal  maxillary  lymphatic  glands. 

From  the  course  of  the  lymphatic  vessels  it  follows  that  in  septic  conditions, 
such  as  infected  wounds,  erysipelas,  and  abscess  of  the  po.sterior  portions  of  the 
scalp,  the  occipital  and  posterior  auricular  glands  may  become  affected,  and  that  in 
the  same  condition  of  the  lateral  part  of  the  scalp  the  parotid  lymphatic  glands 
may  become  enlarged  or  inflamed,  and  septic  matter  from  the  frontal  region  of  the 
scalp  may  eventually  reach  the  submaxillary  lymphatic  glands.  The  course  of 
the  lympliatic  vessels  usually  corresponds  to  that  of  the  veins. 

Metastasis  from  carcinomatous  growths  generally  follows  the  lymphatic 
vessels.  In  septic  conditions  or  carcinomata  of  the  anterior  portion  of  the  face,  of 
the  lips,  of  the  tongue,  and  of  the  sublingual  and  submaxillary  salivary  glands  the 
submaxillary  lymphatic  glands  become  enlarged.  Similar  affections  of  the  outer 
part  of  the  eyelids  and  face  involve  the  parotid  lymphatic  glands ;  and  in  corre- 
sponding conditions  of  the  orbital,  nasal,  temporal,  and  zygomatic  fossa?,  of  the 
deeper  tissues  of  the  cheek  and  of  the  roof  of  the  mouth,  the  internal  maxillary 
lymphatic  glands  may  be  affected. 

Before  dissecting  the  neck,  the  student  should  remove  the  brain  and  place  it 
in  a  solution  to  prepare  it  for  dissection  ;  he  should  study  the  diploic  veins,  the 
dura  mater  and  its  processes,  trace  the  meningeal  vessels  and  the  sinuses,  and 
follow  the  cranial  nerves  to  their  respective  foramina  of  exit  from  the  cranial 
cavity.  These  structures  and  their  dissection  are  described  under  the  Membranes 
and  ^''essels  of  the  Brain. 


THE  MEMBRANES  AND  VESSELS  OF  THE  BBAIN. 

Dissection. — Before  removing  the  calvaria,  or  skull  cap,  entire,  its  outer 
compact  table  should  be  removed  on  one  side,  so  as  to  expose  the  diploe  or  middle 
table,  with  its  bony  channels  for  the  accommodation  of  the  diploic  veins.  This  is 
most  rea<lily  done  by  sawing  through  the  outer  table  in  the  horizontal  line 
described  in  the  removal  of  the  calvaria  as  a  whole,  and  in  the  sagittal  line  of 
the  skull,  when,  with  a  chisel,  it  can  l)e  lifted  off  piecemeal.  To  remove  the  por- 
tion below  tlu^  line  of  llie  horizontal  section  a  Hey's  saw  may  be  used. 

The  Diploic  Veins,  uMincd  from  the  bones  in  which  they  ramify,  are  the 
frontal,  tlie  fronto-sphenoid,  the  fronto-parictal  (anterior  temporal),  the  external 
parietal  (posterior  temporal),  and  the  occipital  (parieto-occipital).    They  vary  greatly, 


PLATE  CLXXIII, 


Anterior  temporal  diploic 
Fronto-sphenoidal  diploic  v. 
Frontal  diploic 


Frontal  sinus 


Occipital  diploic  V. 
Posterior  temporal  diploic  v. 
Mastoid  foramen 


DIPLOIC  VEINS. 
705 


THE  MEMBRANES  AND  VESSELS   OF  THE  BRAIN.  707 

however,  in  (litiercnt  subjects  (Merkel).  These  veins  are  distinct  before  the  cranial 
bones  unite  with  duc  aniptlur,  after  wliich  there  is  a  free  anastomosis  between  them. 
In  young  subjects  tliey  are  small,  hut  they  increase  in  size  as  age  advances  (Quain). 
They  have  no  valves,  and  their  walls  are  extremely  thin. 

The  frontal  veins  are  situated  in  the  anterior  part  of  the  frontal  bone  ;  they 
pass  most  frefjuently  through  the  supra-orbital  foramen  and  empty  into  the  supra- 
orbital vein  ;  they  may,  however,  empty  into  the  fronto-sphenoid  vein,  ^"arico.sity 
of  this  vein,  even  to  the  extent  of  causing  absorption  of  the  outer  table  of  the  bone, 
may  occur. 

The  fronto-sphenoid  veins  lie  in  the  lateral  part  of  the  frontal  and  in  the 
sphenoid  bone  ;  tiiey  enijity  into  the  sinus  ahc  parvir. 

The  fronto-parietal  or  anterior  temporal  veins  are  situated  in  the  posterior 
part  of  the  frontal  and  in  the  anterior  part  of  the  parietal  hone  ;  externally  they 
empty  into  the  deep  temporal  veins,  and  internally  into  the  superior  petro.sal  sinus 
or  a  meningeal  vein. 

The  external  parietal  or  posterior  temporal  vein  is  situated  in  the  parietal 
bone  ;  it  passes  through  a  foramen  in  the  posterior  inferior  angle  of  this  bone,  or 
through  the  mastoid  foramen  to  empty  into  the  lateral  sinus. 

The  occipital  or  parieto-occipital  vein,  the  largest  of  the  diploic  veins,  is  con- 
fined to  the  occipital  bone ;  it  empties  externally  into  the  occipital  vein,  or  inter- 
nally into  the  lateral  sinus. 

In  compound  fractures  of  the  skull  the  diploic  veins  offer  an  opening  favor- 
able to  the  introduction  of  septic  matter  into  the  circulation,  thereby  permitting 
thrombosis  of  the  sinuses,  septic  meningitis,  general  sepsis  (pyemia),  or,  possibly, 
abscess  of  other  organs,  especially  the  liver.  The  diploic  veins  communicate  with 
those  of  the  scalp  by  means  of  very  small  vessels ;  through  these  the  septic  matter 
may  be  conveyed  to  the  diploic  veins  and  thence  to  the  sinuses.  It  is  doubtless 
through  one  or  more  of  these  emissary  veins,  in  the  majority  of  cases,  that  septic 
material — the  result  of  inflammation  of  the  scalp — enters  the  venous  system. 

Dissection. — Remove  the  calvaria  (skull  cap)  by  sawing  through  the  outer 
and  middle  tables  along  a  line  carried  horizontally  around  the  skull,  roniieeting  a 
point  one-half  of  an  inch  above  the  supra-orbital  margin  with  a  point  the  same 
distance  above  the  external  occipital  protuberance ;  then,  with  a  chisel  and  mallet, 
cut  through  the  inner  table,  prying  the  calvaria  from  the  underlying  dura  mater. 
In  breaking  throucrh  the  inner  table  the  mallet  and  chi.sel  are  preferred  to  tlu' 
saw,  there  being  less  danger  of  cutting  the  dura  mater ;  even  when  closely  adhe- 
rent to  the  calvaria.  the  dura  mater  should  only  be  divided  as  a  last  resort.  In 
dividing  the  bone  in  the  temporal  region  its  thinness  must  be  borne  in  mind, 
othei-wi.se  the  brain,  as  well  as  the  dura  mater,  may  be  injured. 


708  SURGICAL  ANATOMY. 

Pacchionian  bodies. — The  outer  surface  of  tlie  dura  mater  being  exposed  by 
removal  of  the  skull  cap,  it  appears  rough,  especially  along  the  lines  of  the  sutures 
and  in  the  neighborhood  of  the  foramina,  where  it  is  most  closely  attached  to  the 
bone.  The  anterior  and  posterior  branches  of  the  middle  meningeal  artery,  with 
the  corresponding  veins,  will  be  seen  to  ramify  upon  the  dura  mater  over  each 
hemisphere  ;  in  most  instances  granular  masses,  the  Pacchionian  bodies,  which  are 
villous  processes  of  the  arachnoid,  will  be  observed  upon  the  surface  on  each  side 
of  the  middle  line.  Tlie  position  of  these  bodies  should  be  carefully  noted,  and 
tliey  must  not  be  regarded  as  jjathologic  when  seen  on  the  operating  or  postmortem 
table.  In  some  cases  they  are  quite  large :  the  avithor  has  known  one  to  be  so 
large  as  to  occasion  sufficient  pressure  to  give  rise  to  focal  (Jacksonian)  epilepsy  ; 
the  patient  was  trephined,  and  the  enlarged  Pacchionian  body  with  the  underlying 
cerebral  cortex  removed,  in  the  belief  that  it  was  a  neoplasm.  The  convulsions  were 
arrested  temporarily,  but  returned  after  a  time;  this,  unfortunately,  occurs  in  the 
majority  of  cases  of  Jacksonian  epilepsy  operated  upon.  These  bodies  are  always 
impressed  upon  the  calvaria,  so  that  depressions,  corresponding  in  size  to  the  bulk 
of  the  bodies  causing  them,  may  be  seen  upon  each  side  of  the  median  line  of  the 
skull ;  at  times  they  almost  perforate  the  bone.  As  a  rule,  they  hollow  the  bone 
out  sufficiently  to  render  it  translucent.  The  existence  of  these  bodies  may,  there- 
fore, be  ascertained  by  inspection  of  the  interior  of  the  calvaria,  and  it  is  even  pos- 
sible, by  the  aid  of  transmitted  light,  to  determine  their  presence  by  examining 
from  without.  The  Pacchionian  bodies,  as  previously  stated,  are  processes  of  the 
arachnoid,  and  serve  as  channels  for  the  passage  of  the  cerebro-spinal  fluid  into  the 
venous  sinuses  of  the  dura  mater ;  in  this  way  they  relieve  intra-cranial  pressure. 
They  vary  greatly  in  size  in  diff'ercnt  persons,  and  in  children  are  quite  small. 

The  dura  mater,  the  most  external  of  the  three  membranes  of  the  brain,  forms 
the  internal  periosteum  of  the  skull,  and  affords  an  excellent  protection  to  the 
brain.  Through  the  medium  of  this  internal  periosteum  the  bones  of  the  skull 
receive  the  greater  part  of  their  nourishment ;  this  explains  why  they  seldom 
necrose  in  scalp  wounds  in  which  the  pericranium  or  external  periosteum  is  torn 
away.  The  dura  mater  is  a  dense,  tough,  inelastic,  fibrous  membrane.  It  is  inti- 
mately adherent  to  the  Ijase  of  the  skull,  owing,  jiartl}-,  to  the  numerous  foramina 
found  there;  therefore,  extra-dural  extravasations  or  collections  of  blood  or  pus 
between  the  dura  and  skull  rarely,  if  ever,  occur  at  the  base  of  the  skull ;  at 
the  sides  and  roof  of  the  cranial  cavity,  however,  where  the  membrane  is  com- 
paratively loosely  attached  (except  along  the  sutures  and  around  the  foramina), 
jiuruliiit  collections  and  extravasations  from  rupture  of  one  or  1)oth  brandies 
of  the  middle  meningeal  artery  are  not  iniconnnon.  These  conditions  cause 
compression  of  titc  hra'm,  the  syinptoiiis  of   which,  coming  on   immediately  after 


PLATE  CLXXIV, 


Orifice  of  superior  cerebral 
Dura  Mater 


Frontal  Sinuses 


Arachnoid 

Dura  Mater 


Middle 
meningeal  a 


Pacchionian  bodies 


Superior  cerebral  v. 
Superior  longitudinal  sinus 


DURA  MATER,  ARACHNOID,  AND  MENINGEAL  VESSELS. 
709 


THE  MEMISRAXES  AXD   VESSELS   OF  THE  BRAIN.  711 

an  injury  to  the  head,  indicate  depressed  fracture ;  if  they  appear  a  short  time 
tliereafter,  hemorrhage  ;  some  days  after,  pus.  Tilhiux  lias  demonstrated  that 
the  dura  mater  is  less  firmly  attached  to  Uj^  temporal  fossa,  the  most  frequent 
site  of  extra-dural  hemorrhage,  tiian  to  any  other  jmrtion  of  the  interior  of  (he 
skull  (Treves).  It  is  most  closely  adher-jut  to  the  houi'  in  iiitaucy  and  nld 
age.  It  has  been  demonstrated  by  .Sir  Charles  Bell  that  the  dura  mater  may 
be  separated  from  the  vault  and  sides  of  the  skull  by  striking  the  head  of  a 
cadaver  a  hard  lilow  with  a  heavy  mallet. 

Extra-dural  hemorrhage. — The  most  common  cause  of  extra-duial  hemorrliage 
is  rupture  of  the  brandies  of  the  middle  meningeal  artery  ;  this  is  usually  associ- 
ated with  fracture  of  the  i)arietal  bone  at  its  anterior  inferior  angle,  the  site  of  the 
groove  through  which  the  anterior  branch  of  the  artery  passes.  The  author  has 
trephined  for  compression  of  the  brain  produced  by  an  extra-dural  clot  not  asso- 
ciated with  fracture.  The  next  most  frecjuent  source  of  extra-dural  hemorrhage  is 
the  lateral  sinus. 

Attachments  of  the  dura  mater. — Besides  being  closely  adherent  to  the  base 
of  the  skull,  the  dura  mater  is  continuous,  tln-ough  the  optic  foramen,  with  the 
periosteum  of  the  orbit ;  through  the  foramen  magnum,  with  the  dura  mater 
of  the  spinal  canal  ;  and  through  the  fissures  and  the  various  foramina  through 
which  the  vessels  and  nerves  enter  and  leave  the  cranial  cavity,  clothed  by 
prolongations  of  this  membrane,  with  the  pericranium.  As  the  dura  mater  is 
directly  continuous  with  these  various  structures,  it  can  be  readily  understood 
how  inflammation  may  extend  by  continuity  into  the  cranial  cavity  and  cause 
secondary'  meningitis. 

Pulsations  of  the  dura  mater. — The  dura  mater,  when  exposed  in  the  living 
subject,  may  present  two  distinct  pulsations,  communicated  from  the  underlying 
brain :  one  synchronous  with  the  pulsation  of  the  arteries,  the  other  with  respira- 
tion, rising  in  expiration  and  sinking  in  inspiration. 

Layers  of  the  dura  mater. — The  dura  mater  consists  of  two  layers  :  an  outer, 
the  endosteal,  and  an  inner,  the  meningeal ;  the  latter  is  lined  by  endothelium, 
which  gives  it  its  shiny  appearance.  Between  the  two  layers  venous  channels  or 
sinuses  and  the  Gasserian  ganglion  are  found.  The  inner  or  meningeal  layer 
sends  in  partitions  which  separate  and  support  the  different  jinrtions  of  the  brain. 

Sarcomata  of  the  dura  mater  may  protrude  through  the  bones  of  the  cranium 
and  cause  a  swelling  in  the  scalp. 

Dissection. — Preliminary  to  removing  the  brain,  and  in  order  to  obtain  the 
most  correct  idea  of  the  normal  relations  of  the  two  larger  j)artitions  formed  by  the 
inner  layer, — namely,  the  falx  cerebri  and  the  tentorium  cerebelli. — divide  the 
dura  mater  in  the  following  manner :  Carry  two  incisions  through  it  from  before 


712  SURGICAL  ANATOMY. 

backward,  one-half  of  an  inch  on  each  side  of  the  median  line,  thus  avoiding  the 
superior  longitudinal  sinus.  From  the  center  of  these  incisions  carry  a  transverse 
incision  upon  each  side  as  far  as  the  divided  margin  of  the  bone.  Reflect  the  flaps 
thus  made,  and  with  the  fingers  gently  separate  the  hemispheres  of  the  cerebrum. 
The  falx  cerebri,  with  the  veins  from  the  surface  of  the  cerebrum  which  empty  into 
the  superior  longitudinal  sinus,  may  then  be  seen.  The  tentorium  cerebelli  can 
now  be  readily,  exposed  by  lifting  up  the  posterior  extremities  of  the  henii- 
spheres  of  the  cerebrum  (occipital  lobes).  Next  lay  open  the  superior  longitudinal 
sinus  and  inspect  its  interior.  Tlie  small  openings  of  the  veins  from  the  top  of 
the  hemispheres  (superior  cerebral  veins),  the  diploe,  and  the  dura  mater  will  be 
seen  along  its  entire  course ;  they  generally  enter  from  behind  forward.  Divide 
the  anterior  uncut  portion  of  the  dura  mater,  and  sever  the  falx  cerebri  from  its 
attachment  to  the  crista  galli,  along  with  the  veins  which  empty  into  the  superior 
longitudinal  sinus ;  together  with  the  falx  cerebri  turn  back  the  strip  of  dura 
mater  in  which  is  contained  the  superior  longitudinal  sinus. 

Removal  of  the  brain. — The  brain  should  now  be  removed  in  the  following 
manner : 

Draw  the  subject  well  up  so  that  the  head  will  hang  over  the  edge  of  the  table. 
With  the  fingers  of  the  left  hand  lift  the  frontal  lobes  of  the  cerel^rum  from  tlie 
anterior  cranial  fossa  and  raise  the  olfactory  bulbs  from  the  cribriform  plate  of  the 
ethmoid  bone,  thus  severing  the  olfactory  nerves.  The  optic  nerves  with  the  oph- 
thalmic arteries  beneath  will  now  be  seen,  and  both  should  be  cut  across  (preferably 
with  scissors),  a  short  distance  from  the  brain.  By  gently  lifting  and  displacing  the 
hemispheres  backward,  the  internal  carotid  arteries  and  the  infundibulum  (a  pro- 
cess of  gra}'  matter  which  connects  the  pituitary  body  with  the  tuber  cinereum)  will 
be  seen.  These  should  next  be  divided  or  the  artery  should  be  severed  and 
the  pituitary  body  removed  from  the  pituitary  fossa  after  incising  the  diaphragma 
selhe.  The  third  pair  of  cranial  nerves,  the  oculo-motor,  will  be  seen  lying 
behind  the  anterior  clinoid  processes  on  their  way  to  reach  the  cavernous  sinuses. 
Divide  these  nerves  and  then,  turning  the  head  to  the  right,  lift  the  temporo- 
sphenoid  lobes  from  the  middle  cranial  fossa,  and  the  tentorium  cerebelli  will 
be  brought  into  view.  This  should  be  cut  through  close  to  its  attachment  to 
tlic  jiostcrior  clinoid  process  and  to  the  petrous  portion  of  the  temporal  bone. 
The  jiathetic,  or  fourth,  and  tlie  trifacial,  or  fifth,  pairs  of  cranial  nerves  should 
be  severed  on  the  left  side  ;  turn  tlic  head  to  the  left,  and  divide  the  corresponding 
structures  on  the  right  side.  Bring  the  face  back  to  the  middle  lino,  draw  the 
l)rain  well  backward,  and  divide  the  following  structures  from  within  outward 
in  tlie  older  named  :  The  abducens  or  sixth,  the  facial  or  seventh,  the  audi- 
tory or  eiglith,  the  glosso-pharyngeal   or  ninth,  the  jDneumogastric  or   vagus   or 


S— 46 


PLATE  CLXXV. 


Veins  of  Galen 


Straight  sinus 


Middle  meningeal  a. 


Inferior  longitudinal  sinus 


Falx  cerebri 


Superior  longitudinal  sinus 


jittu.* 


raU  cerebelli 


Lateral  sinus 


Nasal  septum 


Tentorium  cerebell 
Inferior  petrosal  sinus 


Circular  sinus 


Transverse  sinus 


SINUSES  AND  PROCESSES  OF  DURA  MATER. 
7)4 


PLATE  CLXXVI, 


optic  n 
6th  n_ 


Motor  oculi  n 
4th  n. 


Opthalmic  division  of  5th  n 
Superior  maxillary  n. 
Gasserian  ganglion 
Inferior  maxillary  n 


Foramen  caecum 
.Crista  galli 

Pituitary  body 
Circular  sinus 

Internal  carotid  a. 
Opthalmic  a. 

Cavernous  sinus 


Middle  meningeal  a, 

Superior  petrosal  sinus 


5th  n 


7th  n, 121 

8th  n 


-T. 


"5" 


U^ 


\«fcaltr  )\itrtfh'ili-- 


Lateral  sinus 

\.-  -H     ■ 

Sigmoid  sinus 

Inferior  petrosal  sinus 

Transverse  sinus 

Basilar  plexus 

Occipital  sinus 

Superior  longitudinal  sinus 


SINUSES  AND  CRANIAL  NERVES. 
715 


I 


t 


THE   MI:M11NAXKS   AXn   VESSELS   OE   THE   nEATX.  717 

tenth,  the  spinal  acivssorv  or  olcventli,  and  the  liypo-glossal  <ir  twL'lftli  jiair  ui' 
cranial  nerves.  The  next  and  final  step  consists  of  carryiui;-  a  scal|H"l  down  into 
tiie  spinal  canal  as  far  as  possible  and  cutting  throuiiii  the  spinal  cord,  tln^  two 
vertebral  arteries,  and  the  spinal  ]iortions  of  the  spinal  accessorv  nerves.  The 
lingers  of  tlu'  ritiht  hand  slumld  then  be  slipped  beneath  the  cerelK'lhmi  and  inm^^, 
and  the  lii'ain  I'einoveil. 

Preservation  of  the  brain. — If  the  brain  bo  not  dissected  at  onei-,  it  should  be 
placed  in  a  solution  of  ehlorid  of  zinc,  in  alcohol  and  fonnaldehyd,  or  Midler's 
tluid.  If  placed  in  the  zinc  solution,  the  pia  mater  should  l>e  removed  later,  for  if 
allowed  to  ri>niain  in  this  solution  for  some  time,  it  is  more  easily  separated  than 
in  the  fresh  condition.  If  alcohol  alone  l)e  used  to  pi-eserve  the  l)rain,  the  pia 
mater  must  be  removed  before  placing  it  therein  ;  this  is  most  readily  done  under 
water  ;  liut  if  preserved  in  alcohol  and  formaldchyd,  the  membrane  may  be  removed 
at  leisure.  Brains  hardened  in  ehlorid  of  zinc  shovdd  afterward  be  kept  in  alcohol. 
"When  the  brain  has  been  removed  from  a  subject  injected  (embalmed)  with  ehlorid 
of  zinc,  the  pia  mater  can  at  once  be  separated  and  the  brain  placed  in  alcohol. 
If  the  brain  from  a  fresh  sulvject  be  immediately  jilaeed  in  ale(.)hol,  suljseqvient 
removal  of  the  jna  mater  will  l.)e  foiuid  almost  imjiossible  on  account  of  its  tlrm 
adherence.  If  the  pia  mater  is  not  removed,  the  study  of  the  convolutions  is 
much  less  .satisfactory.  Brains  which  have  been  hardened  in  ehlorid  of  zinc  and 
afterward  kept  in  alcohol  are  much  easier  to  handle  than  when  kept  in  zinc  alone, 
as  the  latter,  by  its  action  on  the  skin,  makes  the  fingers  sticky.  Brains  preserved 
in  alcoliol  and  formaldehyd  are  preferable  to  those  preserved  in  a  solution  of  zinc 
cldorid  and  alcohol,  because  they  are  not  shrunken  so  much  as  the  latter.  Brains 
taken  from  a  subject  embalmed  with  zinc  ehlorid  should  be  hardened  in  a  solution 
of  the  same ;  only  fresh  brains  should  be  hardened  and  preserved  in  alcohol  and  a 
two  per  cent,  solution  of  formaldehyd. 

Processes  of  the  dura  mater. — The  dura  mater,  through  duplication  of  its 
inner  or  meningeal  layer,  sends  three  larger  and  five  smaller  partitions,  folds,  or 
processes  into  the  cavity  of  the  skull  and  between  certain  divisions  of  the  brain  ; 
these  afford  support  to  the  latter.  The  three  larger  processes  are  the  Jalx  ecrcJiri, 
the  tentorium  ccrcbelli,  and  the  falx  ccrebelli.  The  five  smaller  processes  or  folds 
comprise  two  pairs  and  a  single  one.  Of  the  two  pairs,  the  larger  are  attached  to 
the  lesser  wings  of  the  sphenoid  bone  and  project  into  tlie  Sylvian  fissure.  The 
smaller  pair,  crescentic  in  shape,  are  attached  to  the  clinoid  processes  and  over- 
hang the  optic  nerves.  The  single  fold  of  the  smaller  group  stretches  across  the 
pituitary  fossa  covering  the  pituitary  body,  and  is  known  as  the  diapln-afim  of  the 
pituitary  fossa ,  or  diaphragma  sellx.  Its  center  contains  an  opening  for  the  passage 
of  the  infundibulum. 


718  SURGICAL  ANATOMY. 

The  falx  cerebri  is  a  sickle-shaped  process,  narrowed  almost  to  a  point  in  front, 
where  it  is  attached  to  the  crista  galli ;  it  is  broad  behind,  where  it  is  attached  to 
the  middle  of  the  upper  surface  of  the  tentorium  cerebelli.  It  projects  into  the 
great  longitudinal  fissure  of  the  brain  and  separates  the  hemispheres  of  the  cere- 
brum. Its  convex  upper  border  is  attached  upon'  the  inner  surface  of  tlie  calvaria 
to  the  edges  of  the  groove  which  accommodates  the  superior  longitudinal  sinus. 
The  concave  lower  border  is  free,  arches  over  the  corpus  callosuni,  and  contains 
the  inferior  longitudinal  sinus. 

The  tentorium  cerebelli  is  a  somewhat  triangular-shaped  process,  having  its 
base  attached  upon  the  inner  surface  of  the  occipital  bone  to  the  edges  of  the  groove 
for  the  lateral  sinuses  ;  the  sides  are  attached  to  the  line  of  junction  of  tlie  upj^er 
and  posterior  surfaces  of  the  petrous  portion  of  the  temporal  bone,  from  the 
apex  of  which  they  are  continued  to  the  posterior  and  anterior  clinoid  processes. 
The  apex  corresponds  to  the  free  edge,  which  forms  the  lateral  and  posterior  boun- 
daries of  the  triangular  opening  known  as  the  superior  occipital  foramen  or  superior 
foramen  magnum.  This  foramen  gives  passage  to  the  crura  cerebri,  the  superior 
peduncles  of  the  cerebellum,  the  oculo-motor  and  pathetic  neiwes,  and  the  basilar 
artery.  The  tentorium  cerebelli  projects  into  the  great  transverse  fissure  of  the 
brain  and  sej^arates  the  posterior  lobes  of  the  cerebrum  from  the  cerebellum.  In 
the  convex  border  of  the  base  of  the  tentorium  cerebelli  the  horizontal  portions  of 
the  lateral  sinuses  are  contained ;  in  the  sides,  the  superior  petrosal  sinuses  ;  and 
in  the  middle,  at  its  union  witJi  the  falx  cerebri,  the  straight  sinus.  The  base  of 
the  falx  cerebri  is  attached  along  the  entire  median  line  of  the  upper  surface 
of  the  tentorium  cerebelli,  and  the  falx  cerebelli  to  the  median  line  of  the  lower 
surface.  The  tentorium  serves  to  supjjort  the  posterior  lobes  of  the  cerebrum, 
thus  protecting  the  cerebellum  from  pressure. 

The  falx  cerebelli  is  a  small,  vertical  fold  attached  posteriorly  to  tlie  internal 
occipital  crest  or  inferior  vertical  limb  of  the  occipital  cross,  and  above  to  the  under 
surface  of  the  tentorium  cerebelli ;  it  is  situated  between  the  hemispheres  of  the 
cerebellum.  In  its  posterior  border  is  contained  the  occipital  sinus.  This  border 
at  times  splits  into  two  parts,  which  are  attached  to  the  sides  of  the  back  part  of 
the  foramen  magnum. 

Sinuses  of  the  dura  mater. — The  sinuses  of  the  dura  mater  are  venous  chan- 
nels formed  l)y  the  separation  of  its  endosteal  and  meningeal  layers,  and  are  lined 
by  a  prolongation  of  the  lining  membrane  of  the  veins.  They  are  rigid  tubes, 
wliich  always  remain  patent  (Macewen) ;  their  function  is  to  return  the  venous 
blond  from  the  brain  and  its  coverings,  the  diploe  (with  a  few  exceptions'),  and 
al.so  the  greater  part  of  the  blood  from  the  orbit  and  eyeball.  They  collect  this 
blood  and  c(jiivey  it  to  the  jugular  or  posterior  lacerated  foramina,  where  it  is  taken 


THK  MEMnjiAXES  AXD   VESSELS   OF  THE   III: AFX.  719 

up  liy  the  intrrnal  jufjular  veins.  There  arc  sixteen  in  all,  and  tiiey  consist  of 
two  jjjroups  :  those  situated  at  the  uj)per  and  baelv  part  of  tiic  eranial  ravity,  and 
those  situated  at  the  base  of  tlie  sicuU.  The  former  grou[)  includes  tiie  superior 
longitudinal,  tlie  inferior  longitudinal,  the  straigiit,  the  lateral,  and  the  occipital 
sinuses.  Tiie  last-named  group  iucludes  the  cavernous,  the  sinuses  ahe  parvie, 
the  circular,  the  superior  petrosal,  the  inferior  jictrosal,  and  the  transverse.  They 
can  also  be  divided  into  a  median  and  a  latei'al  grouj),  the  former  including 
the  single  sinuses,  situated  in  the  middle  line  of  the  skull,  and  the  latter  the 
paired  sinuses,  situated  on  both  sides  of  the  middle  line.  Five  are  in  jjairs  and 
six  are  single.  The  five  pairs  are  the  lateral,  the  superior  petrosal,  the  inferior 
peti'osal,  the  cavernous,  and  the  sinuses  akc  parv;e.  The  six  single  sinuses  are 
the  superior  longitudinal,  the  inferior  longitudinal,  the  circidnr,  the  transverse, 
the  straight,  and  the  occi})ital.  Some  anatomists  describe  the  sigmoid  portions 
of  the  lateral  simises  as  an  additional  pair,  thus  making  the  number  eighteen. 

The  superior  longitudinal  sinus,  which  has  already  been  expo.sed,  occupies 
the  convex  border  of  the  falx  cerebri.  It  passes  from  the  foramen  cecum  at  the 
root  of  the  frontal  crest  through  the  mesial  groove  on  the  inner  surface  of  the  cal- 
varia  ;  deviating  slightly  to  the  right  in  the  piosterior  part  of  its  course,  it  runs  to 
the  internal  occipital  protuberance,  to  end  in  the  torcular  Heropliili.  The  torcular 
Hcfophili  is  the  point  of  confluence  of  the  superior  longitudinal,  lateral,  straight, 
and  occipital  sinuses,  and  is  situated  a  little  to  the  right  of  the  internal  occipital 
protuberance.  The  superior  longitudinal  sinus  is  triangular  on  section,  the  base 
being  directed  toward  the  calvaria  ;  it  is  narrower  in  front,  gradually  increasing  in 
width  as  it  passes  backward.  Its  lumen  is  crossed  by  a  number  of  fibrous  bands, 
the  cliordie  Willisii,  and  Pacchionian  bodies  are  frequentlj'  found  projecting  into  it. 
It  receives  veins  from  the  scalp  through  the  parietal  foramina,  from  the  diploe,  the 
dura  mater,  and  the  hemispheres  of  the  cerebrum.  These  veins,  particularly  those 
from  the  cerebrum, — the  superior  cortical,— run  into  the  sinus  from  behind  forward 
in  the  direction  opposite  to  that  in  which  the  blood  current  passes;  furthermore, 
they  pierce  the  wall  of  the  sums  veiy  obliquely.  In  the  fetus  the  sinus  com- 
municates with  the  veins  of  the  nose  by  a  small  emis.sary  vein  which  passes 
through  the  foramen  cecum,  but  this  seldom  occurs  in  the  adult.  The  superior 
longitudinal  sinus  presents  a  variable  number  of  lateral  outgrowths  or  pouches, 
which  have  been  named  the  lacunee  laterales.  It  is  into  these  that  the  Pacchi- 
onian bodies  project. 

Wounds  of,  and  line  for,  the  superior  longitudinal  sinus. — The  relation  of 
the  sinus  to  the  skull  renders  it  likely  to  be  wounded  in  compound  fracture  of  the 
vertex,  and  in  trephining  operations  over  the  median  line  of  the  vertex.  Hemor- 
rhage from  this  or  any  of  the  sinuses  is  best  controlled  by  plugging  with  sterile 


720  SURGICAL  ANATOMY. 

gauze,  unless  the  wound  be  small,  in  which  case  it  can  be  closed  by  sutures.  The 
course  of  the  sinus  is  represented  on  the  scalp  liy  a  straight  line  drawn  from 
the  root  of  the  nose  over  the  median  line  of  the  vertex  to  the  external  occipital 
protuberance. 

Septic  or  infective  processes  of  the  scalp  may  enter  the  superior  longitudinal 
sinus  througli  the  parietal  emissary  veins ;  septic  processes  of  the  nose  may  reach 
that  sinus  through  the  vein  in  wliich  the  sinus  has  its  origin. 

Tlie  lateral  sinuses,  the  largest  of  the  cranial  sinuses,  extend  from  the 
internal  occipital  protuberance  to  the  jugular  foramina,  terminating  at  the  begin- 
ning of  the  internal  jugular  veins.  They  arise  on  each  side  of  the  internal 
occipital  protuberance,  across  which  they  are  connected  by  a  small  branch ;  thence 
they  pass  outward  and  forward,  grooving  the  squamous  portion  of  the  occipital,  the 
posterior  inferior  angle  of  the  parietal,  the  mastoid  portion  of  the  temporal,  and 
the  jugular  process  of  the  occipital  bone.  Each  sinus  consists  of  two  portions,  a 
horizontal  and  a  sigmoid.  The  horizontal  portion  is  situated  in  the  base  of  the 
tentorium  cerebelli ;  it  is  triangular  on  section,  the  base  of  the  triangle  being 
directed  toward  the  occipital  bone  and  the  posterior  inferior  angle  of  the  parietal 
bone.  The  sigmoid  portion  is  situated  below  the  tentorium  cerebelli,  and  grooves 
the  mastoid  jiortion  of  the  temporal  and  the  jugular  process  of  the  occipital 
bone  ;  it  is  semicylindric  on  section,  and  is  considered  by  some  anatomists  a 
separate  sinus — the  sigmoid.  The  superior  petrosal  sinus  empties  posteriorly  into 
the  sigmoid  portion  of  the  lateral  sinus  at  its  origin.  The  lateral  sinus  varies 
somewhat  in  size  and  position,  a  foct  to  be  remembered  in  trephining  operations. 

Tributaries  of  the  lateral  sinus. — The  right  lateral  sinus  is  usually  larger  than 
the  left ;  it  begins  at  the  torcular  Herophili,  and  is  the  continuation  of  the 
superior  longitudinal  sinus.  The  left  lateral  .sinus  is  the  continuation  of  the 
straight  sinus.  In  addition  to  the  superior  petrosal  sinuses,  the  lateral  sinuses 
receive  emissary  veins  from  the  scalp,  which  pass  through  the  mastoid  and  pos- 
terior condyloid  foramina  ;  veins  from  the  diploe  (the  occipital  and  the  external 
parietal) ;  the  lateral  inferior  cerebral,  and  some  of  the  superior  and  inferior 
cerebellar  veins. 

Leeching. — A  suitable  site  for  applying  leeches  in  meningitis  is  behind  the 
ear ;  in  this  way  blood  is  extracted  directly  from  the  lateral  sinus  through  the 
mastoid  emissary  vein,  thus  depleting  the  intra-cranial  circulation.  Another,  but 
less  favorable,  location  for  the  application  of  leeches  in  meningitis  is  near  the 
inner  canthus  of  the  eye,  where  the  angular  vein  anastomoses  with  the  ophthalmic 
vein. 

Thrombosis  of  the  lateral  sinus. — The  sigmoid  portion  of  the  lateral  sinus, 
or  the  sigmoid  sinus,  is  the  portion  of  the  intra-cranial  venous  circulation  most  con- 


PLATE  CLXXVIl, 


' Hariiantel^par  ^Lafera/  sinus 


LINtS  FOR  SINUSES. 
721 


THE  MEMBRANES  AND  VESSELS   OF   THE  BRAIN.  723 

cerneil  in  diseases  of  tlic  miildle  oar.  Thrombosis  of  tliis  portion  of  tlie  sinus  and 
of  the  commencenunit  of  the  internal  jugular  vein  constitutes  one  of  the  conipiiea- 
tidus  <if  suppurative  middle  ear  disease,  and  is  due  to  the  proximity  of  the  sinus 
to  the  middle  ear  and  mastoid  cells,  and  to  the  fact  that  veins  i)ass  directly  from 
the  mastoid  portion  of  the  temporal  bone  to  the  lateral  sinus.  This  condition 
demands  exposure  of  the  sinus  and  removal  of  the  clot;  this  is  best  done  before 
general  systemic  infection  lias  occurred.  When  sepsis  is  present  and  the  mastoid 
antrum  has  been  drained  by  trephining  the  mastoid  process  witlmut  producing 
the  desired  effect,  the  sigmoid  jjortion  of  the  lateral  sinus  should  be  exposed 
witliout  delay.  The  presence  of  a  clot  can  readily  be  determined  by  palpation  ; 
removal  of  the  clot  should  immediately  be  followed  by  antiseptic  packing  of  the 
sinus.  The  four  most  serious  complications  of  "suppurative  otitis  media  are  septic 
thrombosis  of  the  lateral  sinus,  septic  meningitis,  abscess  of  the  temporo-sphenoid 
lobe  of  the  cerebrum,  and  cerebellar  abscess. 

Infective  processes  may  also  reach  the  lateral  sinus  from  the  scalp  through 
the  mastoid  vein,  occipital  diploic  and  posterior  temporal  diploic  veins,  and 
through  the  superior  longitudinal  and  the  cavernous  smus. 

Line  for  the  lateral  sinus. — Tn  trephining  for  depressed  fracture  of  the 
occipital  bone,  cerebellar  tumor,  cerebellar  abscess ;  in  opening  the  mastoid  cells  or 
mastoid  antrum  ;  or  in  exposing  the  sinus  itself  in  septic  thrombosis,  it  is  highly 
important  to  bear  in  mind  the  relation  of  the  lateral  sinus  to  the  exterior  of 
the  skull.  Its  course  is  represented  as  follows :  Draw  a  line  from  the  external 
occipital  protuberance  to  a  point  an  inch  above  the  external  auditory  meatus.  The 
sinus  follows  this  line  as  for  as  the  base  of  the  mastoid  process ;  thence  it  runs 
downward  parallel  with  the  middle  line  of  the  mastoid.  According  to  Macewen, 
the  right  sigmoid  groove  is  generally  wider  and  deeper,  projects  farther  outward, 
and  reaches  farther  forward  than  the  left  sigmoid  groove.  The  closer  proximity 
of  tlie  sigmoid  portion  of  the  right  lateral  sinus  to  the  middle  ear  perhaps 
explains  the  greater  frecjuency  of  intra-cranial  lesions  consecutive  to  right-sided 
otitis  media. 

Operations  on  the  mastoid  process. — In  opening  the  mastoid  cells  or  mastoid 
antrum  it  is  better  to  expose  the  entire  surface  of  the  mastoid  process  by  turning  up 
a  large  flap,  than  to  expose  a  limited  surface  through  a  vertical  incision  Ijchind  the 
ear  ;  this  is  particularly  the  ca.se  if  the  disease  be  advanced,  when  the  overlying  soft 
parts  become  .so  swollen  as  to  render  it  impossible  to  outline  the  process  with  any 
degree  of  certainty.  When  the  mastoid  process  is  exposed,  draw  two  lines — a  hori- 
zontal one  thi'ough  the  roof  of  the  external  auditory  meatus,  and  a  vertical  one 
through  its  posterior  wall.  In  adults  apply  the  trephine  or  gouge  at  a  point  a 
little  below  the  horizontal  and  behind  the  perpendicular  line  ;  in  children  apply 


724  SURGICAL  ANATOMY. 

tlie  insti'ument  at  a  point  diroetly  over  the  horizontal  and  liehind  tlie  perpendicu- 
lar line.  With  the  trephine  or  gouge  make  an  opening  in  a  ibrward  and  inward 
direction.  Having  removed  the  external  table,  the  mastoid  antrum  can  usually  be 
entered  with  a  small  elevator  or  a  stiff  director  ;  this  is  to  be  preferred  to  the 
trephine  or  gouge,  as  it  lessens  the  risk  of  injuring  the  sigmoid  poi'tion  of  the 
lateral  sinus.  Both  the  tympanum,  or  middle  ear,  and  the  mastoid  cells  can 
be  drained  through  the  mastoid  antrum.  In  the  majority  of  cases  the  pus  is 
]irimarily  in  the  tymj^anum,  yai  occasionally  suppuration  takes  place  ah  origive 
in  the  mastoid  cells.  It  must  not  be  forgotten  that  in  children  and  in  many 
adults  there  are  no  well-developed  mastoid  cells ;  opening  directly  into  the  mastoid 
antrum  is,  therefore,  the  safest  course  to  jnirsue  in  all  cases. 

The  inferior  longitudinal  sinus  is  situated  in  the  free  concave  margin  of  the 
falx  cerebri.  It  is  of  small  size,  cylindric  on  section,  and  terminates  in  the  straight 
sinus  at  the  junction  of  the  falx  cerebri  with  the  anterior  margin  of  the  tentoiium 
cerebelli  and  at  the  posterior  boundary  of  the  superior  occipital  foramen.  It 
receives  veins  from  the  falx  cerebri,  the  median  surface  of  the  cerebral  hemi- 
spheres, and  the  basilar  surface  of  the  frontal  lobes. 

The  straight  sinus  is  formed  by  the  union  of  the  inferior  longitudinal  sinus 
with  the  veins  of  Galen.  It  is  situated  at  the  junction  of  the  falx  cerebri  with  the 
tentorium  cerebelli,  and  terminates  at  the  internal  occipital  protuberance,  whence 
it  is  continued  as  the  left  lateral  sinus.  It  is  triangular  on  section  and  increases 
in  size  as  it  passes  backward.  It  receives  veins  from  the  tentorium  cerebelli 
and  the  upper  surface  of  the  cerebellum  (the  superior  cerebellar).  Its  direction 
is  downward  and  backward. 

The  occipital  sinus  is  formed  by  the  union  of  two  small  veins  (marginal 
sinuses)  which  pass  around  the  lateral  margins  of  the  foramen  magnum  and  com- 
municate with  the  sigmoid  portion  of  the  lateral  sinus  near  tlie  jugular  foramen 
and  with  the  posterior  spinal  veins.  It  pa.sses  along  the  attached  margin  of  the 
falx  cerebelli  to  the  internal  occipital  protuberance,  where  it  empties  into  the  tor- 
cular  Herophili.  It  may  empty  into  one  of  the  lateral  sinuses  or  into  the  straight 
sinus.  It  receives  veins  from  the  tentorium  cerebelli  and  cerebellum,  communi- 
cating also  with  the  vertebral  veins  and  the  anterior  spinal  plexus. 

The  sinus  alae  parvae,  or  spheno-parietal  sinus,  one  of  the  paired  sinuses, 
occupies  a  groove  on  the  inferior  surface  of  the  lesser  wing  of  the  sphenoid  bone, 
;ind  runs  through  the  sphenoid  fold  of  the  dura  mater.  This  fold  is  attached  to 
tiie  base  fif  the  lesser  wing  of  tlie  s])hen()id  bone,  and  is  continuous  with  the 
dura  mater  at  its  attachment  to  the  anteriur  clinoid  ])rocess.  It  empties  into 
the  cavernous  sinus,  and  oilen  receives  the  froiito-splienoid  veins  of  the  diploe  as 
tributaries. 


THE  MEMBRANES  AXP   VHSSHLS   OF   THE  BRAIN.  725 

Tlic  cavernous  sinuses  aiv  situatnl  along  the  sides  of  the  Ixuly  of  the 
splieiioiil  l)one,  aiul  extend  fnnn  hciieath  the  anterior  ehnoiil  processes  to  the 
apices  of  tlie  [letrons  portions  ol'  tlie  temporal  hones.  The  outer  wall  of  tlu'  sinus 
— the  most  distinct — contains  the  tiiird  and  fourth  nerves  and  the  ophthalmic 
division  of  the  lifth,  while  the  inner  -wall  contains  the  internal  carotid  artery,  the 
sixth  nerve,  and  the  cavernous  plexus  of  the  sympathetic.  "Tillaux  alludes  to 
some  cases  of  aneurysmal  comnuuiication  hetween  tlu'  internal  carotid  artery  and 
the  simis  ;  the  signs  of  such  lesion  are  dilataliiui  of  the  o|ihl]iahnie  \'ein  and  a  pul- 
satory swelling  behind  the  internal  angular  process  of  the  frontal  hone  "  (Owen). 
The  endothelial  lining  mendirane  of  the  sinus  prevents  the  blood  from  coming  into 
contact  with  the  nerves  and  artery.  Practically  speaking,  the  inner  wall  of  the 
sinus  does  not  exist  as  a  distinct  lamella,  but  is  formed  liy  the  structui-es  pre- 
vionsly  enumerated  as  being  contained  therein.  Section  of  the  sinus  discloses 
numerous  iiamls  and  spaces  on  its  interior — hence  its  name.  The  nerves  which 
occupy  the  outer  wall  of  the  sinus  observe  the  same  order,  both  from  above  ilown- 
ward  and  from  within  outward,  in  which  they  have  been  mentioned.  Of  the 
structui'es  occupying  the  inner  wall,  tlie  sixth  nerve  is  the  most  external.  The 
sinus  receives  the  ophthalmic"  vein  in  front,  and  the  sinus  ala3  parvm  above  the 
third  nerve.  It  connnunicates  with  its  fellow  by  means  of  the  circular  simis,  and 
divides  posteriorly  (at  the  apex  of  the  petrous  jiortion  of  the  temporal  bune)  into 
the  superior  and  inferior  petrosal  sinuses.  It  receives  the  middle  cerebral  veins 
and  those  from  the  basilar  surface  of  the  frontal  lobe,  communicating  with  the 
pterygoid  plexus  of  veins  by  means  of  the  Vesalian  vein,  which  runs  through  the 
Vesalian  foramen  in  the  greater  wing  of  the  sphenoid  bone.  It  also  connnunicates 
with  the  internal  jugular  vein  through  the  venous  plexus  surrounding  the  petrous 
portion  of  the  internal  carotid  artery,  and  with  the  pterygoid  and  pharyngeal 
plexuses  of  veins  by  means  of  veins  -n-hich  run  through  the  foramen  ovale  and 
the  foramen  lacerum  medium. 

Infective  material  may  reach  the  cavernous  sinus  from  the  scal}i  thi-ougb  the 
supra-orliital  or  frontal  and  oidithalmic  veins,  and  through  the  fronto-sphenoid 
diploic  vein  ami  the  sinus  ala;  i)arvrc ;  from  the  orbit  through  the  ophlhahaic 
vein  ;  and  from  the  iiterygo-maxillary  region  through  the  vein  of  \'esalius  and 
cmi.s.sarv  veins  which  pass  througli  the  foramina  at  the  base  of  the  skull. 

Relations  of  the  cavernous  sinus  to  the  Gasserian  ganglion. — But  one  of  the 
cavernous  sinuses  .should  be  opened  at  this  stage  of  the  dissection,  the  opening  of  the 
other  beinff  deferred  until  the  nerves  which  run  in  the  walls  of  the  sinus  to  enter 
the  orbit  have  been  traced.  Upon  opening  the  cavernous  sinus  it  will  be  seen  to 
occupy  an  interval  between  the  endosteal  and  meningeal  layers  of  the  dura  mater, 
as  is  the  case  with  the  other  sinuses.     In  this  interval  Meckel's  space,  which  is 


k 


726  SURGICAL  ANATOMY. 

occupied  l)y  the  Gasserian  ganglion,  raay  also  be  demonstrated  at  tiiis  time.  The 
comparatively  intimate  relation  existing  between  the  sinus  and  the  ganglion  should, 
therefore,  be  borne  in  mind  when  attempting  to  remove  the  ganglion  for  relief 
of  trifacial  neuralgia,  otherwise  the  sinus  might  be  injured  ;  an  accident  of  this 
kind,  it  is  hardly  necessary  to  saj',  might  be  serious. 

The  circular  sinus,  through  which  the  two  cavernous  sinuses  communicate, 
surrounds  the  pituitary  body.  The  anterior  half  is  larger  than  the  posterior,  and 
in  advanced  life  is  larger  than  in  early  life.  At  times  one-half  is  absent.  It 
receives  veins  from  the  pituitary  body  and  the  neighboring  bone  and  dura  mater. 

The  superior  and  inferior  petrosal  sinuses  are  the  terminal  divisions  of  the 
cavernous  sinus.  The  superior  petrosal  sinus  runs  in  a  small  groove  in  the  superior 
edge  of  the  petrous  portion  of  the  temjioral  bone,  in  the  margin  of  the  tentorium 
cerebelli.  It  terminates  in  the  lateral  sinus  at  the  \)C)\\\i  where  the  sigmoid  portion 
of  the  sinus  begins.  At  its  origin  it  is  crossed  by  the  fourth  nerve,  and,  in  turn, 
crosses  the  fifth  nerve.  It  receives  some  of  the  inferior  cerebral  and  superior 
cerebellar  veins,  a  vein  from  the  middle  ear  which  makes  its  exit  through  the 
petro-squamous  suture,  and  some  diploic  veins. 

The  inferior  j)etrosal  sinus,  which  is  shorter  and  wider  than  the  superior,  runs 
in  the  groove  formed  by  the  junction  of  the  inferior  border  of  the  petrous  portion 
of  the  temporal  with  the  basilar  process  of  the  occipital  bone,  and  at  the  jugular 
foramen  empties  into  the  commencement  of  the  internal  jugular  vein.  The 
terminal  portion  of  the  inferior  petrosal  sinus  sejaarates  the  glosso-pharyngeal  from 
the  pneumogastric  and  spinal  accessory  nerves.  It  receives  some  of  the  inferior 
cerebellar  veins  and  some  from  the  medulla  oblongata  and  pons ;  veins  from  the 
internal  ear  which  make  their  exit  by  waj'  of  the  aqueductus  vestibuli  and 
aqueductus  cochlese  also  empty  into  it. 

The  transverse  sinus,  through  which  the  inferior  petrosal  sinuses  commu- 
nicate with  each  other,  passes  across  the  basilar  process  of  the  occiijital  bone.  It 
extends  inferiorly  as  far  as  the  anterior  margin  of  the  foramen  magnum,  where  it 
communicates  with  the  anterior  spinal  veins.  The  sixth  pair  of  nerves  pass 
through  it.  Some  authors  describe  the  transverse  sinus  as  a  plexus  of  veins 
(l)asilar  plexu.s). 

Blood  Supply. — The  blood  supjdy  of  the  dura  mater  is  derived  from  the 
meningeal  arteries,  though  the  chief  function  of  these  vessels  is  to  supply  the  bones 
of  the  cranium.  These  arteries  comprise  practically  three  sets, — an  anterior,  a 
middle,  and  a  ]i()steri()i-, — and  in  the  dried  skull  their  course  can  readily  be  traced 
by  Inllowiiig  the  grooves  in  the  liones  wliich  they  occupy.  The  meningeal  arteries 
are  accomijanied  by  relatively  small  veins. 

Nkkvk  Supply. — The  nerve  supi)ly  of  the  dura  mater  is  derived  from   the 


THE  MEMBRANES  AND   VESSELS   OF  THE  BRAIN.  T21 

Gasserian   ganglion,  the    first,  second,   and   tliinl   divisions  of  the  trigeminal  or 
fifth,  the  pneumogastric,  the  hypo-glossal,  and  the  sympathetic  nerves. 

Dissection. — Before  studying  the  courses  of  tlie  meningeal  arteries,  which 
necessitates  stripping  the  dura  mater  from  the  skull,  examine  the  cranial  m  rxcs 
as  they  pass  through  the  foramina  at  the  base  of  the  skull.  The  dura  nuitur 
should  then  be  disposed  of  in  the  foregoing  manner. 


INTRA-CRANIAL   COURSE  AND   MODE   OF   EXIT   OF   THE   CRANIAL 

NERVES. 

Coverings. — In  tracing  the  cranial  nerves  to  their  exit  through  the  fnnuiiina 
at  the  base  of  the  skull,  ob.serve  that  each  pair  of  nerves  receive  investments  from 
all  three  membranes  of  the  brain.  The  coverings  derived  from  the  duni  mater 
and  the  pia  mater  are  continuous  with  the  sheaths  of  the  nerve,  while  that  from 
the  arachnoid  terminates  as  the  nerves  enter  the  dura  mater. 

Enumeration. — The  names  of  the  twelve  pairs  of  nerves,  mentioned  from 
before  backward,  are  :  The  olfactorj',  the  optic,  the  oculo-motor,  the  pathetic,  the 
trifacial,  the  abducent,  the  facial,  the  auditory,  the  glosso-pharyngeal,  the 
pneumogastric,  the  sjiinal  accessory,  and  the  hypo-glossal  nerves. 

The  olfactory  nerves,  the  first  pair,  consist  of  the  olfactory  tracts  and  bulbs, 
and  have  been  removed  with  the  brain  and  their  branches  divided.  Strictly 
speaking,  the  olfactory  bulb  and  tract  are  to  be  regarded  as  portions  of  the  brain. 
Arising  from  the  lower  surface  of  the  olfactorj-  bulb  are  some  twenty  filaments, — 
the  real  olfactory  nerves, — which  are  arranged  in  two  rows,  an  inner  and  an 
outer.  They  supph'  the  upper  portions  of  the  septum  and  the  outer  wall  of  the 
nose  respectively,  and  terminate  in  cells  in  the  mucous  memlirane.  By  carefully 
separating  the  dura  mater  from  the  grooves  in  the  base  of  the  skull  on  each  side 
of  the  crista  galli,  these  real  olfactory  nen-es  may  be  seen  running  through  the 
foramina  in  the  cribriform  plate  of  the  ethmoid  bone. 

The  optic  nerves,  the  second  pair,  pass  through  the  optic  foramina  accom- 
panied by  the  ophthalmic  artery. 

The  oculo-motor  nerves,  the  third  pair,  pierce  the  dura  mater  near  the  ante- 
rior clinoid  processes,  and  enter  the  outer  wall  of  their  respective  cavernous  sinu.ses. 
In  this  situation  they  lie  above  the  fourth  nerve  and  the  ophthalmic  branch  of  the 
fifth.  They  enter  the  orbits  through  tlie  sj)lienoid  fissures,  and  here  lie  below  the 
fourth  nerve  and  part  of  the  ophthalmic.  They  next  divide  into  two  branches, 
which  pass  between  the  heads  of  the  external  recti  muscles,  separated  from  each 
other  by  the  nasal  branches  of  the  ophthalmic  ners'es ;  they  supply  all  the 
extrinsic  muscles  of  the  eyeball  with  the  exception  of  the  superior  oblique  and 


728  SURGICAL   ANATOMY. 

external  rectus,  and  also  supply  the  circular  muscular  fibers  of  the  iris  and  the 
ciliaiy  muscle. 

The  pathetic  nerves  (trochlearis),  the  fourth  and  smallest  pair  of  cranial 
nerves,  pierce  the  dura  mater  near  the  free  edge  of  the  tentorium  cerebelli,  a  little 
behind  the  posterior  clinoid  processes  and  above  the  oval  openings  for  the  fifth 
nerves.  Each  enters  the  outer  wall  of  its  respective  cavernous  sinus,  where  it 
lies  below  the  third  nerve  and  above  the  ophthalmic  nerve,  and  passes  into  the 
orbit  through  the  sphenoid  fissure,  in  which  it  lies  above  the  third  nerve  and 
the  ophthalmic  division  of  the  fifth.  It  supplies  the  superior  oblique  or  troch- 
learis muscle. 

The  trifacial  nerves,  the  fifth  pair,  have  two  roots, — a  larger  sensorj^  and  a 
smaller  motor, — and  pass  through  an  oval  opening  in  the  dura  mater  beneath  the 
free  border  of  the  tentorium  cerebelli.  Above  the  fifth  nerve  is  the  fourth  nerve, 
and  below  it  are  the  apex  of  the  petrous  portion  of  the  temporal  bone  and  the  inter- 
nal auditory  meatus.  Upon  the  larger  or  sensory  root  is  the  Gasserian  ganglion, 
which  can  not  be  seen  until  the  dura  mater  is  raised  from  the  base  of  the  skull. 
Its  description  will  therefore  be  deferred  until  this  has  been  done.  The  ophthalmic 
branch  of  the  trifacial  nerve  is  exposed,  and  is  seen  running  through  the  outer  wall 
of  the  cavernous  sinus,  where  it  lies  beneath  the  fourth  nerve.  It  divides  into  three 
branches, — the  lacrymal,  frontal,  and  nasal, — after  which  it  enters  the  orbit  by 
way  of  the  sphenoid  fissure.  In  the  wall  of  the  sinus  the  ophthalmic  branch  is 
joined  by  filaments  from  the  carotid  plexus  of  the  sympathetic  nerve,  communicat- 
ing with  the  third,  fourth,  and  sixth  nerves,  and  giving  off  a  recurrent  branch 
which  passes  backward  between  the  layers  of  the  tentorium  cerebelli. 

The  abducent  nerves,  the  sixth  pair,  pierce  the  dura  mater  behind  the  body 
of  the  sphenoid  bone  immediately  below  the  posterior  clinoid  processes,  and  pass 
through  the  transverse  sinus.  Each  then  courses  along  the  inner  wall  of  the  cav- 
ernous sinus  to  the  outer  side  of  the  internal  carotid  artery,  and  enters  the  orbit  by 
way  of  the  sphenoid  fissure,  lying  between  the  ophthalmic  vein  and  the  inferior 
branch  of  the  oculo-motor  nerve.  It  supplies  the  external  rectus  muscle,  between 
tlie  two  heads  of  which  it  passes.  Within  the  wall  of  the  cavernous  sinus  it  is 
joined  by  filaments  from  the  carotid  plexus  of  the  sympathetic  nerve. 

The  facial  nerves,  the  seventh  pair,  leave  the  cranial  cavity  by  way  of  the 
internal  auditory  meatus.  Eacli  nerve  is  accompanied  by  the  pars  intermedia 
of  Wrisberg,  the  auditory  nerve,  and  the  auditory  artery.  At  the  bottom  of  the 
meatus  it  enters  the  facial  or  Fallo])ian  canal.  (For  a  description  of  the  course 
of  tlie  nerv(!  througli  the  facial  canal  see  tlie  Dissection  of  tlie  Internal  Ear.) 
It  lies  within  the  meatus,  first  to  the  inner  side  of,  and  then  directly  over,  the 
anditorv  nerve. 


THE  }rF}rBRANES  AND    VESSELS  OF  THE   /.'/?.  17.V.  720 

The  auditory  nerves,  tlio  i-ighth  pair,  k'avo  the  cranial  cavity  through  tho 
internal  auditory  meatuses  in  company  with  the  auditory  arteries,  the  facial  nerves, 
and  the  pars  interiuedia.  .Reaching  the  bottom  of  the  meatus  each  nerve  divides 
into  two  branches,  the  cochlear  and  tho  vestibular,  for  the  supply  of  the  cochlea, 
the  vestibule,  and  tlie  semicircular  canals. 

The  glosso-pharyngeal  nerves,  tiie  ninth  pair;  the  pneumogastric  (vagus), 
the  tenth  pair ;  aud  the  spinal  accessory,  the  eleventh  pair,  leave  the  cranial 
cavity  by  way  of  the  jugular  or  jjosterior  lacerated  foramen,  passing  through  its 
middle  compartment.  The  glosso-pharyngeal  nerves  have  a  separate  sheath  of 
ilura  mater  and  arachnoid,  and  lie  in  front  of  the  pneumogastric  and  spinal 
accessory  nerves.  The  last-mentioned  two  have  a  sheath  of  dura  mater  common 
to  both,  but  they  have  separate  sheaths  of  arachnoid.  The  spinal  accessory  nerve 
is  made  up  of  two  parts :  a  smaller  or  accessory  portion  (accessory  to  the  pneumo- 
gastric nerve),  which  runs  with  the  pneumogastric,  and  a  spinal,  w'hich  arises 
from  the  spinal  cord,  and  is  by  far  the  larger  portion.  The  latter  enters  the 
cranial  cavity  through  the  foramen  magnum  aud  joins  the  accessory  portion 
shortly  after  the  latter  emerges  from  the  medulla. 

The  hypo-glossal  nerves,  the  twelfth  pair,  leave  the  cranial  cavity  through 
the  anterior  condyloicl  foramina. 

The  internal  carotid  artery. — When  the  cavernous  sinus  has  been  laid  open 
and  the  nerves  within  its  wall  exposed,  carefully  examine  the  internal  carotid 
artery  running  in  the  inner  wall  of  the  sinus  before  disturbing  the  dura  mater 
further.  After  its  exit  from  the  carotid  canal,  the  curves  which  the  artery  makes 
in  reaching  the  brain  can  now  be  seen  to  the  best  advantage.  Having  emerged 
from  the  carotid  canal  the  artery  turns  upward,  passing  toward  the  posterior 
clinoid  process.  It  next  runs  forward  through  the  inner  wall  of  the  sinus  to 
reach  the  inner  side  of  the  anterior  clinoid  process,  where  it  again  turns  upward 
and  pierces  the  dura  mater  on  the  inner  aspect  of  the  anterior  clinoid  process ;  just 
before  piercing  the  dura  mater  it  gives  off  the  ophthalmic  branch.  The  cranial  or 
terminal  portion  thus  makes  two  bends,  which  give  it  the  shape  of  the  letter  S. 
Running  along  with  the  artery  and  external  to  it  is  the  abducent  (sixth)  nerve. 
The  lining  membrane  of  the  sinus  alone  separates  both  the  artery  and  the  nerve 
from  the  interior  of  the  sinus.  Within  the  walls  of  the  .sinus  the  artery  gives  olf 
branches  known  as  the  arteris  receptaculi,  whicli  supply  the  walls  of  the  sinus, 
the  pituitary  body,  the  Gasserian  ganglion,  and  the  dura  mater  (through  the 
anterior  meningeal).  It  is  surrounded  by  filaments  of  the  sympathetic  nerve 
which  form  two  plexuses,  the  carotid  on  the  outer  and  the  cavernous  on  the  inner 
side  of  the  artery.  The  former  plexus  communicates  with  the  abducent  nerve 
and  the  Gasserian  and  Meckel's  ganglia;  the  latter  communicates  with  the  oculo- 
s— 47 


730  SURGICAL  ANATOMY. 

motor,  pathetic,  and  ophthalmic  nerves,  and  furnishes  the  sympathetic  root  to  the 
ophthalmic  or  lenticular  ganglion. 

Dissection'. — The  dura  mater  should  now  be  dissected  from  the  sides  and 
base  of  the  skull ;  it  will  l)e  found  closelj'^  adherent  to  the  latter,  requiring  care  in 
its  removal  in  order  to  avoid  injuring  the  following  structures :  The  Gasserian 
ganglion,  the  superior  and  inferior  maxillary  nerves,  which  are  branches  from 
the  ganglion,  the  large  superficial  petrosal,  the  external  superficial  petrosal 
when  present,  and  the  motor  root  of  the  trifacial  nerve.  The  last  and  the  large 
superficial  petrosal  nerve  run  beneath  the  ganglion. 

The  Gasserian  ganglion  occupies  a  depression  on  the  sujDerior  surface  of  the 
petrous  portion  of  the  temporal  bone  near  the  apex,  and  rests  to  a  slight  extent  on 
the  cartilage  filling  the  middle  lacerated  foramen.  It  holds  an  intimate  relation, 
therefore,  to  both  the  internal  carotid  artery  and  the  ca'^'ernous  sinus.  It  is  cres- 
centic  in  outline,  its  concavity  being  directed  backward  and  its  convexity  forv/ard 
and  outward,  and  it  measures  about  one-half  of  an  inch  in  width.  Its  upper  and 
lower  surfaces  are  slightly  convex.  It  occupies  an  interval  between  the  endosteal 
and  meningeal  layers  of  the  dura  mater  (Mecl-el's  space),  and  for  this  reason  the 
endosteal  layer  of  the  dura  mater  must  be  divided  in  attempting  its  removal 
through  the  side  or  base  of  the  skull.  From  the  convexity  of  the  ganglion  arise 
the  ojjhthalmic,  superior  maxillary,  and  inferior  maxillary  nerves,  the  first  two 
being  sensory  nerves  throughout.  The  inferior  maxillarj'  nerve  is  sensory  until  it 
reaches  the  outside  of  the  skull ;  here  it  is  joined  by  the  motor  root  of  the  trifacial 
nerve,  which  leaves  the  cranial  cavity  with  it  by  way  of  the  foramen  ovale ;  the 
inferior  maxillary  thus  becomes  a  mixed  nerve. 

The  superior  maxillary  nerve,  intermediate  in  size  between  the  ophthalmic 
and  the  inferior  maxillary,  leaves  tlie  cranium  by  way  of  the  foramen  rotundum. 

The  inferior  maxillary  nerve,  the  largest  branch  of  the  fifth,  leaves  the 
cranial  cavity  by  way  of  the  foramen  ovale  which  also  transmits  the  small  super- 
ficial petrosal  nerve  and  the  small  meningeal  artery. 

Intra-cranial  neurectomy  of  the  superior  and  inferior  maxillary  nerves. — 
This  is  one  of  the  operations  for  relief  of  trifacial  neuralgia,  and  is  performed  in 
the  following  manner :  An  i2-shaped  flap  is  made  over  the  temporal  region, 
beginning  near  the  tragus  of  the  auricle  and  carried  upward  to  about  the  level  of  the 
temporal  ridge,  ending  near  the  external  angular  process  of  the  frontal  bone.  .Vll 
tlie  structures  down  to  tlic  bone  are  divided.  They  include  the  skin  and  superficial 
fascia,  the  attrahens  aurem  muscle,  the  temporal  branches  of  the  facial  and  auriculo- 
temporal nerves,  the  anterior  and  posterior  temporal  arteries  and  veins,  the  occi- 
pito-frontalis  aponeurosis,  the  areolar  tissue  layer,  the  temporal  fascia  and  muscle, 
the  deep  temporal  vessels,  and  the  periosteum.     The  bone  is  then  cut  through  in 


k 


THE  MEMBRANES  AND   VESSELS   OF  THE  BRAIN.  731 

the  Hue  of  tlie  orif;in;il  incision,  prcti'i-alily  with  an  instrunu'nt  specially  eon- 
ytrui'(eil  tor  this  purpose.  Caw  nuist  he  taken  to  avoid  injurini;'  tiie  iut'nil)ranes 
of  tile  hrain.  An  elevatof  is  intro(hiceil  heueath  the  hone  alter  it  has  heen 
eut  tin'ough  along  the  whole  line  of  the  ineision,  and  tin-  entire  llap  is  foi-eed 
outward  and  downward.  The  lione  will  fracture  hetween  the  ends  of  the  oval 
inci.sion  a  little  ahove  tiie  line  of  the  zygomatic  arch.  The  bone  and  soft 
structures  should  be  reflected  as  one  llap  in  thus  exposing  the  dura  mater  of  the 
lirain.  When  tlie  middle  meningeal  artery  lies  in  a  canal  in  the  tem]n)ral  and 
])arietal  hones,  it  may  he  toini  in  t'nreing  tiie  flap  downward.  Tliis  necessitates 
tying  the  vessel  or  plugging  the  canal  for  the  vessel  with  gauze,  as  the  bleeding 
would  be  severe.  The  dura  mater  is  separated  from  the  floor  of  the  middle  cranial 
fossa,  and  when  the  brain  is  lifted  upward,  the  superior  and  inferior  maxillary 
divisions  of  the  fifth  or  trifacial  nei-ve  will  be  exposed.  As  much  as  possible  of 
lioth  nerves  is  then  excised,  and  the  distal  ends  pu.shed  through  their  respective 
foramina  of  exit.  The  operation  is  completed  by  repositing  the  flap  of  bone,  sutur- 
ing the  soft  parts,  and  dressing  the  wound. 

Removal  of  the  Gasserian  ganglion. — In  removing  the  Gasserian  ganglion 
one  of  two  routes  can  be  selected,  either  through  the  side  of  the  skull  or  through 
its  base  ;  the  latter  method  was  first  practised  by  Mr.  Rose.  In  the  former  method, 
by  far  the  most  preferable,  an  osteo-plastic  resection  of  the  side  of  the  skull  is 
made,  similar  to  that  in  the  previous  operation.  The  flap  of  ])one  includes 
part  of  the  frontal,  greater  wing  of  the  sphenoid,  parietal,  and  the  squamous 
portion  of  the  temporal  bone.  After  the  superior  and  inferior  maxillary  nerves 
are  exposed,  they  should  be  traced  backward  to  the  Gasserian  ganglion  ;  this 
is  lodged  in  a  depres,sion  near  the  apex  of  the  petrous  portion  of  the  temporal 
hone,  in  a  space  (Meckel's)  situated  between  the  two  layers  of  the  dura  mater. 
The  outer  layer  of  the  dura  mater  should  be  incised,  and  the  ganglion  removed. 
The  inferior  and  superior  maxillary  divisions  of  the  trifacial  nerve  are  then 
resected  up  to  their  point  of  exit  from  the  skull,  and  the  distal  ends  pu.shed 
through  their  respective  foramina.  The  inferior  maxillary  nerve  leaves  the 
skull  through  the  foramen  ovale  ;  the  superior  maxillary  nerve  through  the  fora- 
men rotundum.  Tlie  osteo-plastic  flap  is  then  replaced  and  the  wound  closed. 
The  first  steps  of  this  and  the  succeeding  operation  will  be  greatly  facilitated 
by  the  use  of  an  electric  headlight  attached  to  a  head-band. 

In  the  second  method  the  first  step  consists  of  dissecting  up  a  flap  of  skin, 
superficial  and  deep  fascia  from  the  side  of  the  face,  and  exposing  the  zygoma, 
taking  care  not  to  wound  the  parotid  duct.  The  zygoma  should  be  sawed 
through  at  each  end  and  turned  down,  along  with  the  masseter  muscle.  Next 
divide   the    coronoid  process  of  the    inferior   maxilla    and  turn  it  ujjward  with 


732  SURGICAL  ANATOMY. 

the  temporal  muscle  ;  this  exposes  the  internal  maxillary  artery  and  pterygoid 
muscles.  The  internal  maxillary  artery  should  he  tied  at  two  points  and 
divided.  The  external  pterygoid  muscle  should  then  be  carefully  detached  from 
its  origin,  thus  exposing  the  inferior  maxillary  nerve  as  it  emerges  from  the 
foramen  ovale,  which  is  the  point  at  the  base  of  the  skull  to  be  attacked  with 
the  trephine.  If  the  inferior  maxillary  nerve  has  not  been  removed  by  a 
previous  ojDeration,  it  acts  as  an  important  guide  in  locating  the  foramen.  The 
eminentia  articularis  and  the  root  of  the  pterygoid  process  are  additional  guides, 
the  foramen  being  usually  just  in  front  of  a  transverse  line  drawn  through 
the  eminence,  and  immediately  behind  the  root  of  the  external  pterygoid 
plate.  When  the  foramen  has  been  clearly  exposed,  apply  a  small  trephine, 
one-half  of  an  inch  in  diameter,  to  the  base  of  the  skull  and  remove  a  button 
of  bone  which  includes  the  margin  of  the  foramen.  The  proximity  of  the  fora- 
men to  the  carotid  canal  renders  this  step  a  very  important  one.  The  disc  of 
bone  having  been  removed,  the  exposed  dura  mater,  which  1:)ulges  more  or  less 
into  the  trephine  hole,  should  be  opened  and  the  inferior  maxillary  nerve,  if  not 
already  exposed,  sought.  When  found,  it  is  traced  to  the  Gasserian  ganglion, 
which  is  then  removed  piecemeal.  The  operation  is  completed  by  replacing  the 
tissues  in  as  nearly  tlie  normal  position  as  possible ;  the  zygoma  and  the  bone  on 
each  side  of  it  are  drilled  and  sutured,  drainage  is  introduced,  and  the  wound 
closed.  The  button  of  bone  is  not  replaced.  Extreme  care  should  be  exercised 
throughout  this  operation,  which  is  one  of  great  magnitude.  The  nutrition  of 
the  eyeball  may  be  so  seriously  affected  as  to  result  in  its  destruction. 

Dissection. — To  continue  the  dissection,  divide  the  larger  or  sensory  root  of 
the  trifacial  nerve,  lift  the  Gasserian  ganglion,  and  displace  it  forward  and  down- 
ward so  as  to  better  expose  the  smaller  motor  root  and  the  large  superficial 
petrosal  nerve,  both  of  which  lie  beneath  the  ganglion.  The  motor  root  of  the 
trifacial  nerve  can  be  traced  to  the  foramen  ovale,  where,  with  the  inferior 
maxillary  nerve,  it  makes  its  exit  from  the  skull. 

The  large  superficial  petrosal  nerve  arises  from  the  geniculate  ganglion  of 
the  facial  nerve,  and  will  be  seen  emerging  from  the  hiatus  Fallojiii.  Thence  it 
runs  in  a  small  groove  on  the  side  of  the  superior  surface  of  the  petrous  portion  of 
the  temi)oral  bone  to  reach  the  cartilage  which  fills  the  middle  lacerated  forame: 
It  pierces  the  cartilage  and  is  joined  by  the  great  deep  petrosal  nerve  from  the 
carotid  plexus  of  the  sympathetic,  thus  forming  the  A^idian  nerve. 

The  small  superficial  petrosal  nerve  arises  from  the  facial  nerve,  emerges  from 
the  facial  canal  by  way  of  a  small  i'oramen  situated  external  to  the  hiatus  Fallopii, 
passes  to  the  foramen  ovale,  and  joins  the  otic  ganglion.  Occasionallj''  it  passes 
through  a  small  foramen  situated  between  the  foramina  ovale  and  spinosum. 


THE  MEMBRANES  AXD   VESSELS   OF  THE  BRAfX.  733 

The  external  superficial  petrosal  nerve  loaves  the  facial  nerve  and  canal  l>y 
way  of  a  tsnia  11  foramen  placed  external  to  that  for  the  small  superficial  petrosal 
nerve,  on  its  way  to  join  the  plexus  of  the  sympathetic  upon  the  middle  meningeal 
artery.  This  nerve  is  seldom  found  in  the  dissection  of  the  interior  of  the  huse  of 
the  cranium,  for  in  lifting  up  the  endosteal  layer  of  the  dura  mater  the  petrosal 
nerves  are  very  aj>t  to  he  severed  unless  the  utmost  care  is  ohserved. 

The  Meningeal  Arteries — the  anterior,  the  middle,  the  small,  and  the 
Dsterior  meningeal — run  between  the  skull  and  the  duia  mater,  and  are  apt  to 
be  destroyed,  or  at  least  cut,  when  removing  tlie  dura  mater;  notwithstanding 
this  they  can  be  traced  by  the  grooves  in  the  bones  which  they  occupy.  The 
greater  part  of  the  anterior  branch  of  the  middle  and  the  terminal  part  of  the 
posterior  meningeal  arteries  have  been  observed  when  removing  the  calvaria. 

The  middle  meningeal  artery. — The  largest  and  most  important  of  the 
meningeal  arteries  is  the  middle.  As  seen  when  dissecting  the  pterygo-maxillary 
region,  both  this  and  the  small  meningeal  are  branches  of  the  internal  maxillary 
artery.  The  middle  meningeal  artery  runs  between  the  two  roots  of  the  auriculo- 
temporal nerve  and  enters  the  cranial  cavity  by  way  of  the  foramen  spinosum  ; 
it  occupies  a  groove  in  the  greater  wing  of  the  sphenoid  bone,  and  almost 
immediately  divides  into  two  branches,  the  anterior  and  the  posterior.  Small 
branches  of  the  middle  meningeal  artery  pierce  the  cranial  bones  and  anastomose 
with  the  vessels  of  the  scalp. 

The  anterior  branch  runs  through  a  groove  across  the  great  wing  of  the  sphe- 
noid, and  continues  into  another  groove  in  the  anterior  inferior  angle  of  the  parietal 
bone.  The  commencement  of  this  latter  groove  for  a  distance  of  one-fourth  to  one- 
half  of  an  inch  is  often  bridged  over  by  a  thin  plate  of  bone,  and  is  thus  converted 
into  a  canal.  The  vessel  continues  along  the  groove  near  the  anterior  border  of 
the  parietal  bone,  runs  almost  parallel  with  the  coronal  suture  to  within  a  short 
distance  of  the  superior  longitudinal  sinus,  and  gives  off  branches  which  run 
upward  to  the  vertex  and  backward  toward  the  occipital  bone.  The  sinus 
alffi  parvEe  or  spheno-parietal  venous  sinus  at  times  accompanies  the  artery  for  a 
part  of  its  course,  and  may  conseciuently  be  injured  in  fracture  or  during  the 
manipulations  of  the  surgeon. 

The  posterior  branch,  the  smaller  of  the  two,  crosses  the  squamous  portion  uf 
the  temporal  bone  along  the  line  of  junction  of  the  scpiamous  with  the  petrous  por- 
tion, and  tiien  upon  the  posterior  inferior  angle  of  the  parietal  bone,  where  it 
divides  into  its  branches. 

Extra-dural  hemorrhage. — From  the  relation  which  the  anterior  branch 
of  the  middle  meningeal  artery  holds  to  the  anterior  inferior  angle  of  the 
parietal  bone,  it  follows  that  fracture  of  this  part  of  the  skull  is  apt  to  result 


734  SURGICAL  ANATOMY. 

in  hemorrhage,  which  would  l;ie  located  between  the  bone  and  the  dura  mater. 
The  vessel  may  be  injured  either  by  sharp  bony  spicula  or  by  the  sudden 
alteration  in  shape  to  which  the  skull  is  subjected  in  cases  of  severe  head  injury. 
It  has  already  been  noted  that  the  dura  mater  is  loosely  attached  to  the  vault 
of  the  cranium  ;  this  accounts  for  the  size  of  the  large  extra-dural  blood-clots 
occasionally  seen.  From  the  relation  of  this  l)ranch  to  the  motor  area  of  the 
brain  it  can  readily  be  understood  why  the  symptoms  consequent  ujion  the 
pressure  of  an  extra-dural  clot  are  largel)^  if  not  altogether,  motor.  These 
cases  constitute  an  especially  favorable  class  for  trephining,  which  should  be  done 
as  soon  as  the  diagnosis  is  made,  or  as  early  as  possible.  If  upon  the  removal 
of  the  clot  the  bleeding  has  not  ceased,  the  vessel  should  be  tied.  This  may 
necessitate  enlarging  the  original  trephine  opening  in  order  to  expose  the 
bleeding  points.  The  author  has  found  it  necessary  to  tie  both  the  anterior  and 
the  posterior  branch.  It  occasionally  happens  that  the  injury  to  the  middle 
meningeal  artery  occurs  on  the  opposite  side  to  that  upon  which  the  external 
lesion  exists. 

Point  for  trephining. — The  point  of  election  for  applying  the  trephine  in  a 
suspected  case  of  extra-dural  hemorrhage,  meningeal  in  origin,  is  at  a  point  one 
and  one-half  inches  behind  and  one  inch  above  the  external  angular  process  of  the 
frontal  bone.  When  a  simple  or  a  compound  depressed  fracture  is  associated  with 
the  hemorrhage,  the  trephine  should  be  applied  near  the  fracture.  To  reach  the 
posterior  branch  the  trephine  should  be  applied  immediately  below  the  parietal 
eminence,  and  on  the  same  horizontal  level  as  in  the  preceding  operation.  The 
opening  can  subsequently  be  enlarged  in  a  downward  or  backward  direction  and 
the  vessel  thus  brought  into  view. 

Branches  of  the  middle  meningeal  artery. — The  middle  meningeal  artery 
gives  off  branches  within  the  cranial  cavity  to  the  Gasserian  ganglion  :  a  petrosal 
branch,  which  enters  the  hiatus  Fallopii  to  supply  the  facial  nerve  and  anasto- 
moses with  the  stylo-mastoid  branch  of  the  posterior  am-icular  artery  ;  a  lacrymal 
branch  which  enters  the  orljit  by  way  of  the  sphenoid  fissui'e,  or  b\'  a  separate 
canal  in  the  greater  wing  of  the  sphenoid  bone,  and  anastomoses  with  the  oph- 
thalmic artery  ;  a  branch  to  the  tensor  tympani  muscle ;  and  branches  which 
leave  the  cranial  cavity  through  foramina  in  the  great  wing  of  the  si>henoid 
bone  to  anastomose  in  the  tem]ioral  fossa  with  the  deep  temporal  arteries.  It  is 
accompanied  by  t^vo  veins  which  ('mj)ty  into  the  internal  maxillary  vein. 

The  anterior  meningeal  arteries  are  branches  of  the  ethmoid  arteries ;  they 
supply  the  dura  mater  of  the  anterior  cranial  fossa  in  the  region  of  the  median 
line.  One  of  the  arteria  receptaculi,  derived  from  the  cavernous  portion  of  the 
internal  carotid  artery,  suj)plies  the  dura  mater  of  the  middle  cranial  Ibssa.     It 


THE  MEMBRANES  AND  VESSELS   OF  THE  BRAIN.  735 

anastomoses  witli  tlie  niiddlo  meningeal  artery,  and  it  also  receives  the  name 
of  anterior  meningeal.  The  dura  mater  of  the  middle  cranial  fossa  is  supplied 
chiefly  hy  the  small  meningeal  artery,  a  branch  of  the  internal  maxillary,  which 
enters  the  cranial  cavity  by  waj'  cf  the  foramen  ovale,  and  one  or  two  branches 
from  the  ascending  pharyngeal  artery,  which  enter  the  cranial  cavity  through 
the  middle  lacerated  foramen. 

The  posterior  meningeal  arteries  are  the  cranial  branches  of  the  ascending 
pharyngeal,  the  occipital,  and  the  vertebral  arteries;  those  arising  frcun  llic 
ascending  pharyngeal  and  the  occipital  artery  enter  the  cranial  cavity  by  way 
of  the  posterior  lacerated  or  jugular  foramen,  and  those  from  the  vertebral  artery 
by  way  of  the  occipital  foramen  (foramen  magnum) ;  they  supply  the  dura  mater 
of  the  occipital  or  posterior  cranial  fossa. 

The  ascending  pharyngeal  artery  also  sends  a  meningeal  branch  through 
the  middle  lacerated  foramen,  and  an  occasional  one  through  the  anterior  condy- 
loid foramen. 

The  meningeal  veins,  with  the  exception  of  those  accompanying  the  middle 
meningeal  artery,  empty  into  the  sinuses. 


INDEX. 


In  this  Imlex  the  references  in  heavy-face  type  are  to  the  pages  containing  plates  illustrating  the 
subject  namcil.      Kelerences  in  regular  type  are  to  the  text. 


A. 

Abducent    n.,    4(!.=i,     728,     539. 

IV'/e  Sixth  Cranial  Nerve. 
Abscess  beueatli  temporal  fascia, 

cerebellar,  ■12.'? 

trephining.  511 
cerebral,  42:! 
extradural,    12:5 

trephiiiiiit;,  ."ill 
intra<'ranial,  .511 
nia.stoiil,  420 

of  antrum  of  Highmore,  312 
of  cornea,  3li4 
of  face,  626 
of  frontal  .sinus,  311 
of  laervnial  sac,  644 
of  neek,  31,  47 
of  occipital  trianj;le,  59 
of  pter\f;o-niaxiUary  region, 

692  ' 
of  scalp,  (il7 
orbital,  :52:5 
parotid,  6."i7 

i[icision  for,  6.58 
post-pharvMgcal,  2.32 
t em i>or( (-sphenoid.  .511 
trephining,  511 
Absence  of  iris,  :!(is 
Acces-sory  cartilages  of  nose,  293 

qiiajlrate  «irtilages,  293 
Accommodation,  386 
Acne,  2X5 

Acroniio-thoracic  a.,  133 
Adam's  apple,  23 
Adduction  of  cornea,  348 
Air-chambeis  of  nose,  accessory, 
314 
oritices,  298 
Ala  cinerea,  547,  536,  542,  556 
AliC  of  nose,  2H4 
Alei>ek,  canal,  599 
Alveolar  a..  684,  678 
Am])iilla  of  semicircular  canals, 

4:!2,  439 
Ampiillie  of  semicircular  canals, 

427 
Amputation  of  tonsil,  225 
Amygdala,  562.  560 
Anastomosis  of  angular  a.  644 
of  anterior  temjioral  a.,  606 
of  cerebellar  a.,  posterior   in- 
ferior, 450 
of  cerebral  a.,  453 


Anastomosis  of  cerebral  a.,  ante- 
rior, 446 
posterior,  453 
of  cerebral  a.s,  453 
of  cervical  a.,  ascending,  145 

dee]),  147 
of  coronary  a.,  (i43 

inl'i'rior,  643 
sui)erior,  643 
of  facial  a.,  648 

transverse,  644 
of  frontal  a.,  :i37,  606 
of  inferior  coronary  a.,  643 

labial  a.,  643 
of  infra-orl)ital  a.,  676 
of  lateralis  nasi  a.,  644 
of  lingual  a.,  Ill 
of  mental  a.,  (i76 
of  nasitl  a.,  'S'.i"! 
of  oecipitjil  a.,  006 
of  posterior  auricular  a.,  606 

temporal  a.,  606 
of  princeps  cervieis  a.,  95 
of  ranine  a.,  114 
of  scapular  a.,  posterior,  146 
of  sul)lingual  a.,  115 
of  superior  coronary  a.,  643  . 
of  supra-orbital  a.,  336,  60,5 
of  thyroid  a.,  inferior,  144 
of  transverse  facial  a.,  641 
Ander.sch.  ganglion,  116 
Anesthesia  of  cornea,  379 

temporal  a.  in,  606 
Anenrvsm,  cirsoid,  606,  599 
Angle,'  filtration,  :!91,  394 

of  chamber  of  eve,  anterior, 
:{91 
Angles  of  mouth,  210 
AngtUara.,  6:!-',  611,   608,  613, 
640 
anastomosis,  644 
convolution,   486,  489,  474, 

477 
gyrus.  489,        J'ide  Angular 

Convolution, 
vein,  35,  645 
Aniridia,  :!68 
Anneetant  gyri,  4-^5 
Annular  synechia,  394 
posterior,  :!95 
Annulus  tympanicus,  403 
Anosmia,  302 

Ansa   hypoglossi    nerve,    66,    73, 
71 

737 


Ansa  Vieussenii,  85 

Anterior  chamber  of  eyeball.   17r/c 

Chamber  of  llyebali.  Anterior. 
Antero-lateral  fontanel,  5''1 
Antlielix.       I'iil<  .Xntilic  lix. 
Antihelix,  399,  (Kill.  398.  661 
fo.ssii,  ;!99,  6611,  398,  661 
Antitragicus  in,.  401,  663,  665 
Antitragns,  399,  660,  398,  661 
Antrum,  mastoid,  412,  413 
freiihining,  415 
of  Highmore,  312,  339,  350 
absces.s.  312 
cj-sts,  315 
dropsy,  315 
empyema.  313 
Uiucnet4e,  :',12 
oriliee,  298 
ttnnors,  312 
Anvil,  423.      Vidi'  Incus. 
Aorta,  129,  133,  137 
Aperture  of  laiyii.\,  218 

superior,   2:.i7.    247,  250 
Apex  of  lung,  18 
Aphasia,  .50:! 

Aponeurosis,  palatine,  246.  242 
of  occipito-frfintalis  m,.  615, 

599,  627 
jihary lineal,  2:;i,  229,  243 
suiira-byoid,  98 
Apoplexy,  (liinger,  454 

internal  capsule,  548 
Apparatus,    laervnial,    351,  350, 

355 
Appendages  of  eye,  648 
Aqueduct  of   Svlvius,    537,  483, 

516, 528    529 
Ai)ue(lmtiis  c'nebli-,'1,  434,  436 
oriliee,  430 
vestibuli.  431 
orifice,  430 
A(pieoiis  bunior.  :!92 
Aracluioid.  4:!S 

inembranc'  of  brain.  709 
removal,  -i'.)-* 
Arantius,  ventricle.  54  1 
Arbor  vita;,  567,  516 
Arch,  supra-orbital.  593 
zygoniatie,  .596 
fracture,  .586 
Arches,  branehi.il,  25 

visceral,  25 
Arciform  fibers,  superficial,  .554 
Arcus  senilis,  364 


738 


INDEX. 


Area,  dangerous,  of  eye,  368 

of  muscular  seuse  in  brain, 

500 
of  tactile  sensation  in  brain, 
500 
Areas  of  brain,  motor,  499,  501 
sensori-motor,  500 
sensory,  499,  501 
Areolar  tissue  of  eyelids,  652 

of  scalp,  (>16 
Argyll  Robertson  i)ui)il,  367 
Arnold's  ganglion,  691 

nerve,  81 
Arteria  aberrans,  1 47 

comes  nervi  plirenici,  66 
septum  nariuni,  (!4.'5 
Arterioe  receptaculi,  7"-'9 
Arterial  blood  in  facial  vein,  047 
Arteries  at  base  of  brain,  452 
carotid,  23 

branches,   87 
diagram,  87 
cerebral,  anastomosis,  453 
ciliary,  336,  379 
of  bniin,  445,  444 
of  ear,  665 

of  face,  640,  596,  608,  613 
of  larynx,  263 
of  neck,  ligation,  160 
of  orbit,  334 
of  scalp,   640,  5SS,  (!05,  608, 

613 
of  septum  of  nose,  6  1:1.  608, 
613.  640 
hemorrliage  from,  643 
of  thyroid  gland,  126 
of  tongue,   105 
of  tonsil,  105 

subclavian,     differences     be- 
tween,  128 
to  brain,  jieculiarities,  453 
Artery,  acromio-thoraeic,  133 
alveolar,  O-' 1,  678 
angular.  ()3s,  643,  608,  613, 
640 
anastomosis.  6  13 
anterioramicnlar.  608,  613, 
620,  640 
deepfi-mporal,  683,678, 

682,  686 
dental,  676 
meningeal,  734 
superior  dental,  li-'l.  686 
temporal.  606,603,608, 
613,  640 
anastomosis,  606 
aorta,  129,  133 
ascendini;  eer\ical,  78,  79 
frontal.  447 
])arietal.  447 
]iharyngeal.  105 
auditory,  internal,  450 
aiuicnlar,  95 

anterior.  (it)6,  608,  613, 
620,  640 
anastomosis.  (I0(! 
<leei),   6S3,  682 
of  post-aniieiiiar,  96 
posterioi-,    96,    (i06,    50, 
70,    71,   78,   79, 
203,    603,    608, 
613,    620,    640, 
673 


Artery,  auricular,  anastomosis,  606 
branches,  96 
relations,  96 
axillary,  133 

basilar!,   449,  45tt,  137,  444, 
452 
branches.  450 
bticcal,   684.  678,  682,  695 
carotid,  common.  61,   02,  7  1, 
39     41,    70,   78, 
129,    133.    164, 
174,  177,  229 
anenrysin,  75 
course.  74 
irregularities,  186 
ligation,  75,  179 
collateral  circu- 
lation,     1S5, 
133 
line  for,  20,  27,  67, 

623 
operation  to  expose, 

182 
position.  18 
relations,  71.  180 
external.  62.  50,  70,78, 
105,   133,    177, 
229,   678,    682, 
686 
branches,  1-6 
irregularities,  187 
ligation,  186 

collateral  circu- 
lation, 187 
line  for,  86,  20,  67 
operation  to  expose, 

183 
relations,  86 
internal,    i;2.    119,    41.5, 
729,  50,  70,   78, 
79,     133,     229, 
334,    343,    405, 
444,  452,   715 
course,  729 
irregularities,  196 
ligation,  195 

collateral  circu- 
lation, 196 
line  for,  20,  67 
operation  to  expose, 

183 
relations,  119.  196 
central,   of  retina,  33(i,  380, 

384 
cerebellar,  anterior,    inferior. 
4.50,  444,  452 
po.sterior,    inferior.    449, 
444,  452 
ana.stoniosis,  4.50 
superior,  4.50,  444,  452 
cerebral,  anterior.  44(i,  444, 
452,  513 
anastmnosis,  446 
middle.   4  hi,  444,  447, 
452 
branches.    1 1(! 
posterior,  453.  444,  452 
anastomosis.  453 
cervical,   ascendinn,  111.  70, 
78,  79,  138 
anastomosis,  145 
deep,  147 

anastomosis,  147 


Artery,   cervical,  superficial,   59, 
146,  133 
transverse,    146.         Vide 
Artery,    Transversalis 
Colli, 
choroid,    anterior.   449,  444, 
452 
posteiior,  444,  452 
ciliary.  377 

anterior,   336,  379,  377, 

384 
posterior,  334 

long.  336,  379,  377, 

384 
short.  336,379,  377, 
384 
circumflex,  anterior.  133 

posterior,  133 
comnion  carotid.  623 

line.  623 
coiinnunieating  anterior,  446, 
444,  452 
posterior.  446,  444,  452 
conjunctival,  384 
coronary,  inferior,  of  lip,  64.3, 
608.       613, 
640 
anastomosis,  643 
course,  643 
superior,  of  lip.  643.608, 
613,  640 
anastomosis.  643 
crico  thyroid,    91,   78,    123, 

251 
deep  auricular,  683.  682 

temporal,  anteiior,   678 
posterior,  683,  678, 
682 
dental,  anterior,  682 

superior,  6s  I.  695 
inferior.  6^3,  678,  682, 

686,  695 
middle  superior,  695 
posterior,  6S4.  682 
descending  palatine. (i84,  682 
dii)loic,  of  supraorbital,  336 
dorsalis  lingua-.  114,  105 

scapula",  133 
esophageal,   of   inferior  thy- 
roid. 145 
ethmoid,  337 

anterior,  307,  337,  334 

branches,  337 
liosterior,   307,  337,  334 
external  carotid,  678,  682, 
686 
]itervi;(iid,  lisl,  682 
f.acial,  92.   50,    70.    78.    79, 
105,   133,  608,  613, 
620,  621    640 
anastomosis.  64-i 
brani-bes,  643 
cervical  portion,  92 

liranches,  92 
course,  638 
irregnlarities,  190 
ligation.  190 
line  for,  20,27,67,623 
operation  toexpose,  182, 

183 
relations,  6:'i8 
transverse.    608,     613, 
620,  640,  678 


IXDKX. 


739 


Artery,  facial,  niiastnmosis.  fill 
fioiital,  I!:;:.  (KK;,  603.  608, 
613,  620   640 
aiiasliiiiHwi^,  :'>:',t,  liiui 
asciMiiliiifi,  447 
iiilVrii)r,  447 
of  aiiU'iiiir  ctliiiioiil.  ;i:57 
gaiifc' ionic.      Miitcro  -  lateral, 
444 
antiTD-iMcdiaii,  444 
postciK-iiu'diaii.  444 
gingival,  682,  695 
hyaldicl,  ;i^<.") 
Iiyi)iil.  -^li 
incisive,  i\<'<.  682 
iufeiior  ciii'iiiKii  V,  of  li|i.  iH'.i, 
608.  613.  640 
anastomosis,  (i  1:1 
conrsc.  (ill! 
dental.    li-^:5,   678,  682, 

686.  695 
laliial.   (!l:!.   608.    613, 
640 
ana.stoniosis.  i>K> 
intra-bvoid.  <d.  50.  70 
infia-oiliiiid,    liTd.  li-l.  620, 
678.  682.  686.   695 
anastomosis.  iJ7(i 
innominate,   78,   129,  133, 
164 
l.ifmvation.  70,  78 
gni<li-  to,    l(i(> 
iiTcgularities.  16G 
ligation,   ICIO,  Ifi.i 

collateral     circnlar 
tion.  l(j.'> 
line  for.  20 

operation  to  e.\|)o.sp,  164 
pnlsations,  is 
relations.  IG.i 
intercostal.  133 
first,  H7 

superior,  147,  133,  137 
internal  carotid,  7^9,  715 
course,  7'3!) 
niaxlllaiv.  UTH.  u-n.  G20, 
621.    678     682, 
686.  695 
liranclies,  ^i<^ 
divisions,  (W:! 
jiterygoid,  6^1.  682 
labial,    inferior,    608.    613, 
640.  682 
ana.stoniosis.  1!4:? 
lacrymal,  :?2:?,  :5:5(i,  334 

branches,  330 
laryngeal,  inferior,   1 1.">.  'Ko, 
263 
of  inferior  thyroid.   1  1.") 
superior.    'Jl,     ii'<'>.     50, 
70     78,     123,     251, 
263 
lateral  nasal,  613 
lateralis  nasi,  64  1 

anastomosis,  04 1 
lenticnlo-striate,    1  Hi 
lingual,  !il,  11  1.  50   70,  78, 
79.  105,  133,  177 
anastomosis,  114 
irregularities.  190 
ligation.  04.  l-^-*,  177 
line  for.  20,  67 
operation  to  expose.  183 


Artery,  lingual,  relations,  02 
malar,  of  lacrymal,  330 
maniniar\,  inlernal,  1  10,  78, 

79,  129,  133 
ma.sseieric,    0-1,    621,    678, 

682 
mastoid,  'Xk  90 
ma.\illar\'.  interna].  0"!i.  (1-0, 

0S3.  133.  620.  621.  678. 

682.  686.  695 
meningeal,  anterior,  734 

middle,  .'>:i-.'.    li-:"..   7:r,, 

303  682.  686. 
690.  695.  709, 
714.  715 

laanelies,  733,  731 
uound,  734 
of  anterior  ethmoid,  337 
ofascending  jiharvngeal, 

97 
posterior,  O.'),   449,    73.5, 

444, 
small.     0-^3,     73,".,    682, 
686.  695 
mental,  070,  (;-3,  620.  682, 
695 
anastomosis,  070 
middle   meninL;eal.  .'i9'.'.  733, 
682     686.    690. 
695.    709.    714. 
715  j 

branches.  733.  734 
wound.  731 
superior  dental.  695 
temporal.      608.      613,    i 
620,  640 
mvlo-livoiil,    1(1 1.    0-:;,  682, 

686.  695 
nasal.  3;!7,  682 

ana.stoniosis.  .337 
lateral,  613 

of  anterior  ethmoid,  337 
naso- palatine,  (\m 
occipital.     9:'..    OdO.    50.    70. 
133.  603,  608,  613 
640 
anastomosis,  00(> 
branches,  94 
irregularities,  I9o 
ligation,  91,  19;') 
operation  to  exi><ise,  183, 

192 
relations.  93 
of  cerebral  hemorrhage.  440 
of  frenuni    of    tongue.     II.t. 

105 
of  spptiun.  397 
oiihthalmic.    33.->.  229,  334, 
444,  715 
branches.  33.") 

niuscnlar.  337 
orbital,  608,  640,  682 
palatine,  a^eeuding,  !>'-' 

deseenditiu,      307,     084, 

105.   682 
of  ascending  pharyngeal, 
97 
palpebral.  682 
inferior.  337 
of  lacrymal,  336 
of  .supraorbital,  .336 
superior,  3:!7 
pariettil,  .i.scending,  447 


Artery,  parieto-teinporal,  447 
parotid,   of  posterior  auricu- 
lar, 9(i 
perineal,    of    female,     trans- 

vi'l'se.  ■Hu 
jieriostetd,     of     sniiraorbital, 

3:'>0 
pharyngeal,     ascending,     97, 
70,  78,  79,  105, 
229 
relations,  97 
of  ascending  pharyngeal, 
97 
posterior  auricular.  OtUi.  603, 
608,  613,  620, 
640,678 
ttnastomosis,  ()(Ki 
dee])  temporal,  0^3,  678, 

682 
dental,  084,  682 
meningeal,  .599 
temiioral.      000,       603, 
608,  613,  640 
aiuistomosis,  000 
prcvcrlebiiil,      of     aseeuding 

pharyngeal,  97 
princeps   cervicis,    95,    133, 
137 
anastomosis,  95 
profunda  cervicis,    174,   133, 
137.      Vide  Deep  Cervical 
.\rterv. 
pterygoid,  678 

'external,  0-4,  682 

internal,  0-4,  682 

ptervgo-palatine.  0-1,  682 

rani'ne,  9-J,  114,  105,  221 

anasttimosis,  114 
recurrent,  of  lacrymal,  330 
retinal.  381 

scapular.  ]iosterior.    .59,    146, 
70.  133 
anastomosis.  140 
small   meningeal,    083,    735, 

686.  695 
splieiHi  palatine.     307.     fiS4, 

682 
spinal,    anterior.    449.    444, 
452 
liitcral,  of   vertebra',  1  13 
])osterior,  449,  444 
sterno-mtistoid,  inferior.  1  10, 
.     70.  78 
mi. idle.  .-.-.  91.   50.   70. 

78.  177 
superior.  9.5.  70.  78 
stvlo-mastoid.  90 
siibdaviaii.  •.':'..  00,  l-.'7.    100, 
50   70,   78,79,   133, 
208 
branclies,   l:!0,  87 
coiii]iressioii.  :-'!'< 
di.igrani,  87 
first  iiortion.  129,  164, 
174 
ligation.       13,"i, 
10(i 
irregularities.  170 
left.  12S 

relations.  128 
ligation,  collateral  oircn- 

laliou.  i:r,,  133 
line  for,  20,  67 


740 


INDEX. 


Artery,  subclavian,  right,  127 
relations.  127 
second  portion,  131 

ligation,       135, 

100 
relations,  131 
third  jjortion,  131 
guide,  17.5 
ligation,      132, 

160,  169 
ligation,    colla- 
teral circula- 
tion, 170 
operation  to  ex- 
pose, 167 
relations,     131, 
160 
variations,  133 
sublingual,  115,  78.  79,  105 

ana.stomosis,  115 
SHbiuaxillarv,  93 
sulmicntal.  93,  50,  70,  105, 
682 
relations,  93 
subscapular,  133 
superficial  cervical,  70 

temporal,      620,     621, 

640,  678.  682,  686 

superior  cuiciiiaiy.  ot'lip.  (i43, 

608,       613, 

640 

anas  to  niosis, 

643 

supra-acromial,    of    s  u  p  r  a- 

scapular,   146 
supra  orliital,  336,  605,  197, 
334,  603.  608,  613, 
620.  640 
anastomosis,  336,  605 
branches,  336 
operation  to  expose,  197 
supra-scapuhir,  0(1,    145,    50, 
70,  78,79,129,133, 
174 
branche.s  146 
relations,  145 
Sylvian,  446 

temporal,  (iOO.  193,  621 
anterior,  lidO,  603,  608, 
613,  640 
anastomosis,  006 
deep,  0S3,678,682, 
686 
in  anesthesia,  606 
middle,  608,  613,  620, 

640 
oiieration  to  expose,  193 
po.sterioi-.       000.       603, 
613,   640,   686 
anastomosis,  ()(.)(J 
deep,  Om:;,  678,  682 
supeitirial,      133,    620, 
621,    640.    678, 
682,  686 
ligation,   195 
thoracic,  long,  133 

sii]MMior,  133 
thyroid  axis,    1  11,    78,    79. 
174 
inferior,  01,  1  11.  20,78, 
119,    133,    174, 
177,  229 
anastomosis,  1  14 


J  yroid,    inferior,   bran- 

ches, 1 14 
irregularities,  179 
ligation,    145,     179, 

177 
line  for,  67 
operation  to  expose, 
174 
superior,  HO,  20,  50,  70, 
78,     105,     123, 
133,    177,     251 
irregularities,  1h,k 
ligation,    187,    177 
line  for,  67 
operation  to  expose, 
183 
thyroidea;  ima,  126,  133 
tonsillar,  93 

of  facial,  105 
of  dorsalis  lingua',  105 
tracheal,  of  inferior  thyroid, 

145 
transversalis  colli,  59,  60, 146. 
50.70,78,  129,  133, 
174,  208 
humeri,  145 
transverse,  facial,  644,    608, 
613.    620,    640, 
678 
anastomosis,  644 
transverse,    of    basilar,    450, 

444.  452 
trochlear,  of  snpra-( irl li tal . 3:!6 
tympanic,  0s3.  682,  686 
of  ascending  pliarvngeal, 
97 
vas  aberrans,  133 
vertebral,  01,  130,    449,    39, 
70,  78,  79,  129,  133, 
137,  152,   164,    174, 
444, 452 
branches,  143 
cervical  jiortion,  136 
guide.  176 
irregularities,   176 
ligation,  143,  175 
occipital  portion,  143 
operation  to  expose,  174 
relations,  136,  175 
vertebral  portion,    136 
Vidian,  684,  682 
Articulation,  crico-arytenoid,  276 
ligaments,  270 
crico-thyroid,  270.  263 

moveinent,s,  270 
of  head,  573 
of  larnyx,  276 
of  neck,  573,  579 
of  .skull,  573 

temporo-maxillary,  573,  576, 
577 
blood-supjily,  574 
inter-articular    fibro-car- 

tiiage,  574 
ligaments,  573 

internal  lateral,   574 
movements,   574 
nerve  supply,  574 
.synovial  membiaiie,  574 
Artificial  mcmlirana  tymi)ani,  420 
Arvtcno-c]iiglotti(lc,in    folds,  24si, 
212  218,236,250,258, 
259 


Aryteno-epiglottidean       muscle, 
201,  258,  259,  263 
action,   202 
insertion,  261 
nerve  supply,  262 
origin,  261 
Arytenoid   cartilage,    275,    267, 

271 
Arvtenoideus  m.,  256,  258,  259, 
263 
action,  261 
insertion,  956 
nerve  su])ply,  256 
origin,   2,56 
Ary-vocalis  of  Ludwig,  20] 
Ascending  cervical  a.,  78,  79 

pharyngeal  a.,    105 
Aspiration  (jf  snliarachuoid  spaxie, 

442 
Asterion,  591 ,  506 
Asthma,  laryngeal,  262 
Astigmatism,   303 
Atrium  of  meatus  of  nose,  299 
Atro])hy  of  testicle,  648 

of  tongue,  220 
Attachments    of  dura   mater    of 

brain,  711 
Attic,  407,  405,  409,  422 
Attolens  auiim  m.,  005,  627 
action,  005 
insertion,  605 
ner\  e  supply,  605 
origin,  605 
Attrahens  aurem  m.,  605,  627 
action,  605 
insertion,  605 
nerve  supply,  605 
origin,  605 
Auditory  a.,  internal,  450 

canal,    external,     403.      Mde 

Auditory  Meatus. 
meatus,  external,  403,    405, 
409 
blood  supply,  404 
lymphatics,  407 
nerve  supply,  407 
occlusion,  404 
relations,  404 
sinus,  403 
veins,  407 
nerve,   438,   405,   729,     539. 
]'Ule  Eighth  Cranial  Nerve, 
ossicles,  423 
striae,  547 
Aural  vertigo,  437 
Auricle,  660,  661 
cartilage,  400 
intcgmnent,  400 
landmarks,  660 
muscles,  intrinsic,  400 
supernumerary,   400 
Auricnlar  a.,  95 

anterior,  606,  608,  613, 
620,  640 
anastomosis,  600 
deep,   0^^;'.,  682 
posterior,  90,  01)0,  50,70, 
71.  78,  79,  203, 
603,    608,    613, 
620,  640.678 
anastomosis,  606 
branches,  96 
relations.  96 


L\ni:x. 


741 


Auricular   Iiraiicli  <it    aiiricularis 
iiia^iuis  11.,  28 
of  pdsUTior  auricular  a., 
'.Hi 
fistiiliv,  1(11) 
lympliatic  glamls,  702 

vessels,  (ilT) 
nerve.  Ml,  Oiili 
anteridr,  (>-!■< 
Sitat.  30,  609 
IMisteriiir,    117.    lil'-',    51. 
70,  71,  78,  79,   203 
region,  ilisseetioii.  (!UII 
vein,  posterior,  "Ki,    35,    50, 
51,  70,   645 
Anrieularis   iiiamiii-i   ii,,  32,    38, 
34,  51 
Iiraiu-lies.  38 
relations,  20f> 
iVnriculoteinporal    n.,    20."),   (!12, 
(W<,     193,     303, 
609,    613,    620, 
686,  -678,    690, 
695 
ili\  isions,  038 
operation  to  exiJOse, 
2ir>,  193 
Axillaiy  a.,  133 

nerve  jilexiis.  14^.    J'ide  Bra- 
cliial  Xerve  I'lexus. 
Axis  of  evelnill,  357 
Az\>;os  u'vuhe  m.,  24(i,  242,  243 
aetion,  246 
insertion,  246 
origin,  246 


Eanil,    furrowed,    of   cerebellum, 
562 
liorn.v,   526 
Bartholin,  dnct,  1 14 
Base  of  brain,  458 

arteries,  452 
structures.  456 
of  no.se,  2s!4 

of  skull,  dislocation,  579 
fracture,  5.s.-,,   (;;)2 
Basilar  a.,  449,    551),    137,  444, 
452 
branches,  450 
plexus,  714 
Bichat,  fissure,  467.  533 
Bifurcation  of  inuoininate  a.,    70 
Bimanual  examination  of  female, 

(i(>2 
Bisentral  lol)e of  cerebellum,  560 
Blaiidin,  uland,  219 
Blindness,  word-,  503 
Bodv,  ciliarv,  368 
geniculate,  538 

external,  538,  463.  539, 

552 
intcriKil.  5:is,  463.  539. 
542,  552,   556.   560 
of  coqjus  callosum.  516 
of  fornix,  522,  533.  546 
of  lateral  ventricle,  518,  519, 

529,  569 
olivary,  554,  458.  539.  552 
corpus  deiitatum,  554 
pe<lunclc,  554 


Body,    jiineal,    538.  S. 

539.   542.   -JO,  ji-0 

prdiiiicl,'.      516.     529, 

536,  542.  556 

)iituilai\,     343,   458,   516. 

539.  552,   565,  715 
restironu.     554,     557,      536, 

542.   556 
siibllialamie,  553 
thyroid.  39 
\"itri'ons,  38.5 
I'.one.  cheek,  596 

frontal,  sinuses,  591 
hyoid.  23,  281,  109 
turbinated.  296 

inferior,  299,  350 
middle,  299.  350 
superior,   299 
Hones,  nasil,  286 

of  face,  fracture,  586 
of  skull,  development,  584 
I'.owinan,  memlirane,  363 
IJiaehia  of  nates.  543 

of  testes,  543 
Brachial  monoplefiia.  501 

nerve  ple.xns,    60.    14x.    51, 
71,  149,  208 
br.-inclies,  148 
di.s.sectioii,  148 
formation,  148 
line   for,  20,  67 
Stretchiiif;.  209 
Brain,  arachnoid  membrane,  709 
areas,  motor,    199,  501 
sensory,  499,  501 
arteries.  445,  444 

peculiarities,  453 
base,  458 

arteries,  452 
structures,  456 
centers,  motor.  500 
compression,  708 
contour,  456 

convolutions.      I'/r/r  Convolu- 
tions of  Brain, 
delinitioii,  455 
di.ssrctiou,  455 
divisions,  455 
foreiKU  bodies,  511 
fissures.         Tide    Fis.su're    of 
Brain, 
line,  506 
gyri.       J'idc  Convolutions   of 

Brain, 
large,  455 

lobes.       fide  Lobes  of  Brain, 
lobules.        Vide  Convolutions 

of  Brain, 
lymphatits,  445 
membranes,   438,  704 
nuclei.  536 
jireservation,  717 
removal,  712 
section,  507 

coronal,  567 
sjigittal,  567 
small,  455 
sulcus.        }'ide     Fi.sstire     of 

lirain. 
variations,  510 
veins,  454 
ves.sels,  438,  704 
weight,  455 


Branchial  arches,  25 
cyst,  26 
lurrow,  26 
'.realhing.  stertorous,  637 
Iregina,  573,  SWM,  506 
'.ridge  of  nose,  2^4 
Iroca's  region,  503 
Ironchus,  left.   129 
Buccal  a.,  (isl,  682,  695 

branch   of    cer\  ico-facial   n., 
6(i9 
of  facial  n.,    609,    613, 
620 
cavitv,  209 
glaoiis.  213.  638 
lyin]ihatic  glands,  702 
lierve,   688,  678,  686,    695 
orifice,   210 

portion    of     Htenson's    duct, 
659 
Buccinator   m..  637,    229,    242, 
621,  627,  678,   686 
action,  63^ 
insertion,  t;37 
nerve  supplv,  638 
origin,  637 
relations,  637 
Bnceo-pharvngeal  I'asciii,  213,  637 
Bulbof  coiniia,  iiostnior,    of    lat- 
eral ventricles,  529 
of  |H'iiis,  .553 
olfa<Morv.  456,  458,  483 
Bulbs  of  fornix,  4(iO 
I'.ulla  ethmoidalis.  299,  315,   298, 

314 
Bundles  of  Vicq  d'Az.vr,  522 
Bursa,  ]iliaryngeal,  232,  233 
sublingual,   21(i 
thyro-hyoid,  255 
Bursa;  of  neck,  156 


C. 

Calamus  scriiitoriiis,  547 
Calcar  avis,  491,  521,  531 
Calciu-iiu-  lissnie,   175,   491,   488, 

494,  497,  516 
Callosal  fissure,    496,    488,   497, 

516 
Calloso-mai'ginal  fissure,  470,  4-'9, 
496,  474  477,  480,  497,  516 
Canal,    auditory,    external,     403. 
]'idi    Meatus,   Auditorv. 
hyaloiil.  3S5.  392 
laerviiial,  352 
of  ('lo(|net.  385 
of  His,  125 
of  llimnii'r,  691 
of  Petit,  38(!,  360 
of  Sehlemm,  362,  360,  365, 

384.  394 
of  Stilling.  :'.s5 
semicircular.   i:il.   427 
ampulla.  4:!2 
external.      427,       430, 

439 
membranous,  437 
posterior,      426,      430, 

439 
superior.  427,  430,  439 
spiral.  432 
Vidian,  309 


742 


INDEX. 


Canalis  centralis  modioli,  432 

reuniens,  4H7,  439 
Cancrum  oris,  626 
Cantluis,  external,  648 

internal,  648 
Capsular  ligament  of  crico-aryte- 
noiil  articulation,  276 
of      teraporo  -  niaxillarv 
articulation,  573,  576, 
557 
ligaments  of  tympanum,   425 
Capsule,  external,  548,  546,  565, 
569 
internal,  547,  565,  569 
genu,  548 
in  apoplexy,  548 
liiiil),  anterior,  547,  546 
posterior,    547,  546 
of  lens,  3U1 

of  Tenon,  324,  342,  320,  321 
of  thyroid  gland,  126 
Carbuncle  of  neck,  26 
Carcinoma  of  l)reast,  pain,  45 
Cardiac  n.,  78,  79 

cervical,    of  pneumogas- 

trie,  83 
middle,  85 

sympathetic,  inferior,  85 
superior,  84 
Caries  of  incus,  424 
of  malleus,   424 
of  vertebrae,  682 
Carotid  arteries,  23 

branches,  87 
diagram,  87 
artery,  682 

common,  61,  62,  74,  39, 
41,  70,  78,  129, 
133,     164,    174, 
177,   229 
aneurj'sm,  75 
course,  74 
irregularities,  186 
ligation,  75,  179 
collateral  circu- 
lation,     185, 
133 
line  for,  20,27,  67, 

623 
operation  to  expose, 

182 
position,  l^* 
relations,  74,  180 
external.  62,  50,70,  78, 
105,   133,    177, 
229,  678,  686 
oranohes,  86 
irregularities,  187 
ligation,  186 

collateral  circu- 
lation, 187 
line  for,   ,^6,  20,  67 
operation  to  expo.se, 

183 
relations,  86 
internal.  62.  119. 445. 729, 
50.    70.    78,  79, 
133,    229,    334, 
343,    405,    444, 
452, 715 
course,  729 
irregnlarities,  196 
ligation,  195 


Carotid  artery,  internal,  ligation, 
collateral   circula- 
tion, 196 
line  for,  20,  67 
operation  to  expose, 

183 
relations,  119,  196 
liranch  of  glosso-pharvngeal, 

116 
lol)e  of  parotid  gland,  656 
sheath,  66 

contents,  73 
lympathie  glands,  73 
triangle,   inferior,  54,  61,  55 
contents,  61 
dissection,  61 
suiieridi',  54,  62.  55 
contents.  62 
dissection,  62 
tubercle,  24,  152 
Cartilage,    arvtenoid,    275,   267, 
271 
cricoid,  21,   274,    123,    251, 
254,  258,  259.  263, 
271 
ossification,  271 
cuneiform,    274,    218,    236, 

250,  271 
lateral,  of  nose,  inferior,  286 

superior,  286 
of  pinna,  665 
of  Santorini,  275 
of  Wrisberg,  274 
septal,  of  nose,  293,  291 
tarsal,  593,  652 
thyroid,  23,   273,   123,  251, 
254,  258,  259,    271 
fracture,  274 
ossitication,  274 
Cartilages,  accessory  quadrate,  293 
of  auricle,  4(10 
of  larynx,  270.  271 
of  nose,  286,  290 
acces.sorv,  293 
lateral,  L'SO,  287 
se.Siimoid,  293 
Cartilago  triticea,  255,  254,  263 
Caruncnla  lachrvmalis,   648,   651, 

649 
Cataract,  391 
Catarrh,  nasiil,  301 
Caudate  nucleus,    ,525,    547,  529, 
542,  546,  556,  565, 
569 
head,  536,  564 
Cavernous  sinus,  725,  715 

relation  of,  to  Gasserian 

ganglion,  725 
sections.  343 
Cavity,  buccal.  209 
Cavuin    seike,    212,    296,    298, 

314 
Cells,  ethmoid,  315,  321 
ma.stoid,  412.  416,  413 
sphenoid,     315.     212,    296, 
298,  309,  714 
Center  of  heariuL;,  503 
of  sm(41,  503 
of  taste,  .503 
of  touch,  .503 
of  vision,  503 
Centers  of  l)rain,  motor,  500 
Central  a.  of  n't  iua,  336,  360, 384 


Central  fissure,  475 

lobe  of  cerebellum,  .561 

of  cerebrni)].  47n 
vein  of  retina.  360,  384 
Cerebellar  abscess.  423 
trephining,  511 
arterv,  anterior  inferior.  450, 
444.  452 
posterior    inferior,     449, 
444,  452 
anastomosis,  4,50 
superior,  450,  444,  452 
veins.  454 
Cerebellum.  .5.5vJ,  458.  477.  516, 
536.  560 
amygdala,  562 
arbor  vit.t,  .567 
corims  dentatum,  567 
fissure,  great  horizontal,  561, 
560 
superior,  561 
flocculus,  51)2 
folium  cacuniiuis.  561 
furrowed  band.  5()2 
bemisj)lieres,  461 
interior  arrangement,  567 
lamina',  5.58 
laminated  tubercle,  562 
lingnla,  561 
lobe,  biventral.  560 
central,  561 
digastric,  562 
posterior    inferior,    562, 
560 
superior,  5lil,  560 
quadrate,  561,  560 
slender,  560 
lobes,  5.58,  561,  562 
lobule,    crescentic,   anterior, 
560 
posterior,  560 
lobulus  centralis,  561 

gracilis,  562 
monticulus  cerebelli,  561 
nodtde,  562 
peduncles.  562 

inferior,    567,  539.  542 
middle.  .567,   458,  539, 

542.  552 
superior,  513,  567,    536, 
539,    542 
position.  4.55 
pjramid.  562 
relations,  558 
tonsil,  562 
tuber  vah'ula?,  562 
uvula,  562 
vallecula,  .558 
vermiform  process,  561 
inferior,  562 
superior,  561 
Cerebral  abscess,  423 

arteries,  anastomosis,  453 
artery,    anterior,     4  16,   444, 
452,  513 
anastomosis,  416 
middle,  4  16,  444,  452 

l)ranches,  4  l(i 
posterior,  4.53.  444,  452 
anast(nnosis,  453 
fissures,  lines,  589 
ganglia,  anterior,  525.     Vide 
Corjins  Striatum. 


L\DI':X. 


743 


Cerebral   gaiifrlia,  posterior,  52(). 
l7</c  Optic  Tlialamus. 
lii'inorrhage.  a.  of.  -1 10 
vein,  supenor,  709 
Cerebro-spiiKil  fluiil.  44'J 
circulation.  H2 
Cercbntin.  4(17.  477 

coiniuissnre,  anterior.  565 

middle,  569 
convolutions,  4(!-*.     I ■/</<■  Con- 
volutions of  Itrain. 
cortex,  disease,  ,")(ll 
crns,  552 
diagram,  474 
dissection.  4(>7 
libel's,  conniii.S'^ural,    longitu- 
dinal, 0-I9 
transverse,  549 
peduMcnlar,  ,548 
fissures,  4(i-<.      ]'i<lc  Fissures 
of  Bfain. 
coniitlete.  4(19 
incomplete,  4l>9 
])rimary,  470 
interior,  dissection,  .")12 
lobes,  469.       I'iile    Lobes   of 

Brain, 
lower  level.  507 
peduncles,  4lilt.  ,">.")0 
position,  4.">.5 
section,  horizontal.  513 

transverse,  546 
surface  anatfiniv.   lH-i 
inferior.  4i38.  497 
internal,  ,510 
median,  488.  497 
veins.  454 
white  matter,  518 
Cervical  a.,   ascendin^i,    144,    70. 
78.  79.  133 
anastomosis,  145 
deep.  147 

anastomosis,  147 
.superficial,    .59,  146,   70, 

133 
transverse,    59.     I'itle 
Transver.s;ilis     Colli 
.\rter.v. 
fascia,  deep,  45 

course,  46 
diagram,  41 
flstuliE,  congenital,  25 
ganglion  of  sym|)athetic,  in- 
ferior, ~i5 
middle,  S4 
superior,  •^4 
lymphatic  glan<l,   deep,    157 

superticial,  !!7,  157 
nerve,  eighth.  149 

anterior  division,  79 
fifth.   149 

a  n  t  eri  o  r  division, 
39,  71,  78 
first,  539 
fourth,  149 

anterior  division, 
71,  78 
ple.vns,  4-^.  65,  44 

branch,  descending, 

45,  51 
branches,  48 

descending, 
208 


Cervical  nerve  jilcxus,  branches, 

superficial,  ^^i 

sn])i'a  acromial, 

34 
s  u  ])  r  a  -  c  I  a  v- 

icular,  34 
s  npr  a  -sternal, 
34 
(lissi'ction,  38,  65 
second,  anterior  division, 

71,  78 
sevenlh.  149 

a  11 1  c  r  i  CI  V  division, 
71,  78 
sixth,  149 

anterior  d  i  \  is  i  on, 
39,  71,  78 
suiierlicial,  45.  34,  51 

relatimis,  2(16 
third,   anterior  division, 
71,  78 
portion    of     svmpatliitic  n., 

<i 
vein,  ileep,  96.  147.  35,  645 
superticial,  70 
Cervical  is  ascendens  m.,  39 
Chamber   of   eye,    anterior,    391, 
360.  369.  394 
angle.  391 
sinus.  391 
posterior,  392,  394 
vitreous,  385,  360 
Prus-sak's,  409 
Chambers  of  eye,  391 

of  nose,  acees.sory  air.  314 
air,  orifice's,  298 
Check    ligament,    external,  324, 
321 
internal,  324,  321 
Cheek  bone,  596 
Cheeks,  213 

Chiasm,  optic,  459,  334 
Chimnev-sweep's  cancer,   640 
Choanal',  232 
Choked  disc,  442 
Chorda    tvm|iani     n..     426.    691. 
422.      678,     686, 
695 
in  Otis  media,  426 
Chorda;  Willisii,  719 
Chorio-capillaiis.  371,  377 
Choroid,  371.  360.  376,  381 
arterv,    anterior,    449,    444, 
452 
posterior,  4.53,  444,  452 
layers,  374 

melanotic  sarcoma,  379 
plexn-.     151,   .526,   514,   519, 
523,  533,  536,546,  565, 
569 
Ciliary  arteries,  336,  379 
ai-tcrv.  377 

anterior,  336,   379,  377, 

384 
posterior,  334 

long,  336,  379.  377, 

384 
short.  336.  ,379.  377, 
384 
body,  368 

ganglion.     338.       J'iilc    Len- 
ticular (l.tnglion. 
branches,  311 


Ciliary    muscle,   3(1-.   360,   365, 
369,  376,  394 
action,  373 
blood  supply,  373 
libers,  373 
nerve  supply,  373 
of  orlticularis    palpcbra- 

1(1111.  (i:i3 

nerve.  376 

long,  335,  376 

posterior,  379,  326, 
377 
short.  379.  339,  377 
]insteiioi.  377 
ner\rs.  ;',79 
process,  360,  365 
pidces.ses,  374,  372 
region  of  eyeball,  372 
section,  365 
V(  in.  anterior,  379,  369.377, 
384 
Cilium,  .■sebaceous  glaiiil.  353 
Cingulum.  517 

Circle  of  Willis,  445.  133,  444 
Circular  sinus,  726,  714,  715 
Circulation,  collateral.      Viik'  Col- 
lateral Circulation, 
of  cerebrospinal  fluid.  442 
Circuluni  iridis  minor.    :',79,   377 

major.  :!79.  377 
Circulus  tonsillaris.  (198 
Circumflex  a.,  aiilrrior,  133 
posteiioi.  133 
nerve,  149 
riiTtimvallale  papilla-,  219,  109, 

218,  236,  250 
Cirsoid  anenrvsm,  606,  599 
Cisterna  hasilis,  441 
magna,  441 
pontis,  441 
subarachnoid,  441 
Claustrum,  548,  546,  564,  565, 

569 
Clava,  5.57 
Cleft  of  iris,  368 
palate,  214 

operation,  215 
soft,  246 
Clivus  of  monticnluscerebelli,  561 
Cloquet,  canal  of,  385 
Coats  of  eye,  361,  369 
fibrous,  361 

dissection,  361 
sclerotic,  3()1 
vascular,  .367 
Cochlea,  4.32.  427,  434,  436 
coliimnella.   132 
cujiola.  432.  427 
nu-nibranous.  437 
modiolus,  432 
vestibule,  427 
Cochlear  duct.  432,  437 

lu^rve,  438 
Collateral    circulation    after  liga- 
tion of  a.,  common 
carotid,  185,   133 
of  a.,  external  caro- 
tid, 187 
of  a.,   internal  caro- 
tid, 196 
of  a.,  innominate.  165 
of     a.,     subclavian, 
135,  133 


744 


INDEX. 


Collateral   circulation  after  liga- 
tiou     of     a.,     siiliclavian, 
third  iX)rtion,  170 
fissure,  41).-!,   488.  494,  497 
C'oloboiiia,  35"^ 
Color  of  iris,  367 
Column    of    medulla    oblongata, 

lateral,  536 
Columna,  nasal,  594 
Columnella  of  cochlea,  43"2 
Comedones,  60)0 

Commissural  libers,  lonjiitudinal, 
of  cerebrum,  549 
transverse,  of  cerebrum, 
549 
Commissure    of    cerebrum,     an- 
terior, 537,  516,  536, 
565 
midilU-,  537,  516,    536, 

542,  569 
palpeljral,  64-< 
posterior,  537,  516.  536 
optic,       459,       458,       483, 
494,  516,  539,  565 
Common   carotid   a.,    line,   623. 
Vide  Carotid  Artery,   Com- 
mon, 
trian.ijle,  anterior,  54 
posterior,   54 
Coiurannicantes,  hypoglossi  n.,  06, 
71 
noui  n.,  66 
Communicatin';  a.,   anterior,  446, 
444,  452 
posterior,  446,  444,  452 
vein,  70 
Communications  of    facial    vein, 

647 
Complexus     m.,    39,     50,     71, 

78 
Compression  of  brain,  70S 

of  subclavian  a.,  23 
Compressor    narium    minor    m., 
627 
na-i  ra.,  629,  627 
action,  629 
insertion,  629 
nerve  supi)ly,  629 
orij;in.  629 
Conarinm,  53-1.    Mile  Pine.il  Body. 
Concha,  399,  060,  398,  661 
Conductor  sonorus,  542,  556 
Condyle   of  inferior  maxilla,   ex- 
cision, 584 
Cone  of  light,  419.  418 
Congenital  cervical  listnhe,  25 
Congestion  of  conjunctiva,  651 
of  frontal  sinus,  311 
of  scalp,  615 
Conic  cornea,  364 
Conjinictiva,  358,  051.  321,  346, 
353,  355.360,365,  369, 
377.  394,  632,  653 
congesti()n,  (J.51 
corneal  portion,  358,  651 

(lestr\iction  of,  3.58 
lialpi-l)ral  portion,  651 
I'cllected  ]»ortiion,  fi51 
sclerotic  portion,  35S,  651 
Conjunctival  a.,  351-1,  384 
papilhe,  353 
vein,  384 
Conjunctivitis,  i)ni'nh'nt,  361 


63, 


;    Constrictor  muscles  of   pharynx, 
;  inferior,    22"*, 

I  71,  79,  123, 

17  7      2  29 
236,  251 
insertion,  228 
origin,  228 
middle,  228,  50,  71, 

79,  105,  229 
SU]ierior.     228,     71, 
79.  229 
muscles   of   pharnyx,     nerve 
supply,  231 
Contents  of  carotid  sheath,  73 
triangle,  inferior,  61 
superior,  (i2 
of  occipital  triangle,  57 
of  parotid  glaud,  657 
of  ptervgo-maxillary  region, 

679   " 
of     spheno-maxillary 

693 
of  subclavian  triangle,  60 
of  submaxillary  triangle, 

98 

of  zygomatic  to.s.sa,  693 
Convergent  sfjuint,  373 
Convolution,    angular,    486,   489, 
474,  477 
cuneus,  491 
dentate,  490,  531 
frontal,  ascending.  482,  474, 
477,  480 
inferior,  482,  474,   477, 

480 
middle,    482,   474,  477, 

480 
superior,  482,  474.  477, 

480 
third,  482 
fusiform,     495,     488,     494, 

497 
hi|i]iocampal,  495,  488,  494, 

497 
infra-marginal, 
lingual,      495, 

497 
marginal,     485, 

516 
occipital,  inferior,    491, 
477,  480 
middle,  491,    474.  477, 

480 
superior,  491,  474,  477, 
480 
occipito-temporal,  495 
orbital,    anterior,    485, 
488,  497 
inferior.  483 
interuiil,  485,  497 
posterior,  485,  483,  488, 
497 
paracentral,  489,    488,    497, 

516 
parietal,  ascending,  4S6,  474, 
477,  480 
inferior,  4S(!.  480 
posterior,  474 
suiierior,  486,   477,  480 
post-central,  480 
post- parietal,  4H9 
precuneus,  489 
(inadrate,  4^9,  488,  497 


492 
488 


494, 
488,    497, 
474, 


483, 


Convolution,  su]ira-marginal,  486, 
4S9,  474.  477 
supra-parietiil,  474 
temporal,  inferior,  492,   47* 
477 
middle,   492,    474,   477 
superior,  492,   474,  477 
temporo-sphenoid,      inferior, 
495,  494 
middle,  492,  494 
superior,  492,  494 
uncinate,  495 
Convolutions,  4(!8 

arrangement,  408 
Cords,  vocal.  24 

false,     248,    266,      212, 

218,  250.  296 
true.      24S',      2il(i.      212, 
218,   250.   296 
Cornea,    .302.   360,     365,    369, 
376.   377,   394 
abscess,  304 
adilnction,  384 
anesthesia,  379 
blood  suppl}',  364 
conic,  364 
depression,  348 
elevation.  348 
layei-s,  303 
lymph  spaces,  392 
movements.  348 
nerve  supiil.v,  364 
rotation,  348 
staphyloma,  364 
ulcers,  363 
wounds,  303 
Corneal    portion    of  conjunctiva, 

358,  651 
Coiniculum   larvngis,    275,    218, 

236,  250,  267.  271 
Cornu  ammonis,  496,  526 
of  lateral  ventricle,  519 

anterior,    .521,    528, 

529,   546 
middle,     .521,     528, 

529 
posterior,  .521,  528, 
529, 546 
bulb,  529 
Corona  ciliaris,  374 
of  glans  penis,  627 
radiata.  548 
Coronal  section  of  brain,  567 

suture,  573,  588 
Coronary  a.,  inferior,  of   liji,  643, 
608,613,640 
anastomosis,  643 
course,  643 
superior,     of     lip,     643, 
608,        613, 
640 
anastomosis,  643 
Corpora     albicantia,     400,     458, 
552,  569 
fimbriata.  .522 

qnadrigemina,       538,       516, 

536.  539,  542 

Corpus  albi.'.iiis.    4011,   51G,   539 

callosum,    159,    107,  512,  513, 

519.    536,  565.   569 

body,  516 

genu.     517.    488,     497, 
516,  523,  564 


r 


INDEX. 


745 


Corpus  callosHiii,  pedmicio,  517 
raphe,  517 
rustniin,  517,488,497, 

546 
spli-niuiii,       517,      483, 
497,  516.  523,    546 
ventiirlc,   l!Mi 
dentatuin  of  eciitnlluiu,  567 

of  olivary  boily,  554 
fiinhriLitiim,   526,   531,   519, 

529 
striatum,  5\>5,  519,  523 
Corrugator     ,suiKTcilii     in.,     ti:i4, 
346,  632 
action,  liHI 
insiTlioii,  (iiil 
lu-rvi'  siipplv,  6:!4 
orifjiii,  (>:i4 
Corte.K  of  cerebrum,  disease,  504 

of  lens,  391 
Corti,  organ,  437 
Cranial   n.,    eighth,    465,     458, 
542,  556.      Vide 
.•\uilit(irv  Nerve, 
origin.  552 
eleventli.  57,    lU(i,   458, 
542.  556 
origin.  552 
fifth,    465,     326.    339, 
458.   542.  556 
oplitlialinic  division, 

326 
origin.  552 
first.  461.    ('('(/<■  Olfactory 

Nerve, 
fourth,    327,    462,    326, 
339,   343.   458, 
542,    556.    560. 
1 7(/<'  P  a  t  li  e  t  i  c 
Nerve, 
origin,  552 
recurrent  lira  uc  h, 
326 
ninth,    466,   458,    542, 
556 
origin,  552 
second,  462,     I7i/(i)ptie 

Nerve, 
seventh,  465,  458 

origin,  552 
sixth,     :!ll,     4ti5,    326, 
339,   458,      Vith-  Ab- 
ducent Nerve, 
tenth,     76,     466,     458, 
542.  556 
oriiiin.  552 
third.     :!ll,    462,     326, 
458.    Vide  Oculo- 
motor Nerve, 
origin.  552 
twelfth,    101,   467,   458 
origin,  552 
nerves,  origin,  452,  715 
superficial  origin,  458 
Craniectomy,  512 
Cranio-eerebral  topography,  499 
Cranium,  bones  of,  5HS 

landmarks,  .5^'7,  589 
Crescentic  lobule  of  cerebellum, 
anterior,  560 
posterior,  560 
Crico-arytenoid  articulation,  276 

S— 48 


Crico-arytenoid  articulation,  lig- 
aments, 276 
ligament,  posterior,  276 

transvei-se,  276 
muscle,  posterior,  263 
Crico-arytenoideus     lateralis    m., 
261,  259 
action,  2(il 
insertion,  2(il 
nerve  supply,  2(il 
origin,  2(il 
posticus    nuiscle,    256,    258, 
259 
action,  256 
insertion,  256 
nerve  sujjply,  256 
origin,  2,">(! 
Cricoid  cartilage,   24,    274,    123, 
251,  254.   258.  259. 
263,  271 
ossification,  271 
Crico-thvroid   a.,  91,    78,     123, 
251 
articulation,  267,  263 

nu)venients,  276 
meinbraiic,     24,     255,     123, 

251,  254 
muscle,  2.55.  123,  251 
action,  255 
insertion,  255 
nerve  supply,  255 
origin,  25,5 
space,  24 
Crista  (ialli,  715 
vestibuli,  431 
Crura  cerebri,   160,  5,50 

of  stajies,  424 
Crural  monoplegia,  .504 
Crus  cerebri.  460,  5.50,  458.  483. 
494.  516.  539,  542, 
552,  556 
crusta,  .553,  488,  497 
tegmentum,    553,    488, 
497 
nuclei,  .5.53 
Crusta   of  crus  cerebri,   460,  553, 

488,  497 
Crypts  of  iris,  392 
of  tonsils,  224 
Crystalline  lens,  386,  360,  372, 
394.      Vi,h'  Lens, 
relations,  386 
Culraen,  560 

of   monticulus  cerebelli,  561 
Cnneate  nucleus,  557 

tubercle,  .557 
Cuneiform    cjiitilage,    274,     218, 

236,  250,  271 
Cuneus,    491,    488,     494,    497, 

516 
Cupola    of    cochlea,       i:!.',      427, 

434 
Cutaneous  n.,  internal,  149 
lesser  internal,  149 
of  perineum,  male,  603 
C.yclon,  368 
Cyst,  branchial,  26 

dermoid,  of  pinna,  400 
seb.aceous,  of  pinna,  400 
Cystotomy,  median  perineal,  622 
Cysts    of    antrum   of  Highmore, 
"315 


Darwin's     tubcrcde,     399,     398, 
401,  527 

Deafness,  424 

word-,  503 
Declive.  .561.  560.      Vide   Clivus. 
Decussjiiiiin    of     iiyramids,     553, 

.554,  458,  552 
Deiters'  nucleus,    165 
Density  of  temporal  fa.si^ia,  618 
Dental  a.,  anterior,  682 

su))erior,  684,  695 
inl'eridi-,  6s:!,    678,  682, 

686,  695 
middle  superior,  695 
po.sterior,  6-<l,  682 
nerve,  anterior  snpeiinr,    697, 
595 
inferior,  691,  678,   686, 
695 
line  for,   20,  67 
operation  to  expose, 

182 
resection,  200 
middle      superior,      694, 

695 
IKisteriiir    superior,     694, 
678,  695 
Dentate  convulution,  496,  531 

fissure,  496 
Dentition  with  otitis  media,  426 
Depression  of  cortu-a,  347 
Depres.sor  al»  nasi  m..  630 

action.  630 
insertion,  630 
nerve       supply, 

630 
origin,  630 
anguli  oris  m.,  636,  627 
action,  636 
insertion,  6.36 
nerve      supply, 

636 
origin,  636 
relations,  636 
labii  iuferiori.s  ni.,  636,  627 
action,  636 
insertion,  636 
ner\e        supply, 

63*; 
origin,  636 
relations,  636 
Dermoid  cyst  of  pinna,  400 
Desceniet,  niend)rane  of,  363 
Descendens  hypoglossi  n.,  73,  41, 
51,  71,  78 
noni  n.,  73 
Descending    branch     of     cervical 
ple.xus,  45,  51 
palatine  a.,  684,  105,  682 
Destruction  of  conjunctiva,  385 
of  tegmen  antri.  420 
tympaui,  420 
Development  of  bones  of  skull,  584 
of  neck,  25 
of  i)inna,  400 
Deviation  of  nasal  se|ittim,  294 
Diagram  of  carotid  a..  87 
of  cerebrum.  474 
of  cervical  fascia,  deep,  41 
of     membranous     labyrinth, 
439 


^■46 


INDEX. 


Diagram  of  optic  tract,  463 
of  subclaxiaii  a.,  87 
of  triangles  of  neck.  55 
of   ventricles  of   brain,    528, 
529 
Diameter     of     eyeball,     sagittal, 
357 
transverse,  357 
vertical,  357 
Diaphragm,  faradization,  155 
of  month,  107 
of  pitnitary  fossa,  717 
Diaphragma  selUc,  717,  212,  296, 

298,  314 
Digastric  fossa,  oltl 

lobe  of  cereljellnm,   563 
nerve,  669 

muscle,  98,  71,  78,  79,  105, 
117 
action,  98 
anterior  ))elly,  50 
blood  supply,  98 
insertion,  98 
nerve  supply,  98 
origiu,  98 
posterior  lielly,  50 
relations,  98 
triangle,  54,  63 
dissection,  63 
Dilator  naris  m. ,  629 

action.  629 
insertion,  629 
nerve  .supply,  629 
origin.  629 
narium  m.,  anterior,    627 

posterior,  627 
tub:e,  408 
Diploe,  599 

Diploic  brancli  of  supraorbital  a. , 
336 
vein,  704,  705 
Diplopia,  316 
Disc,  choked,  442 
Disease,  JK^niere's,  437 

middle  ear,  420 
Diseases  involving  facial  v.,  647 
Dislocation  of  base  of   skull,   579 

of  lower  jaw,  579 
Dissection  of  auricular  region,  660 
of  brachial  nerve  plexus,  148 
of  brain,  455 
of  Ciirotid  triangle,  inferior,  61 

superior,  62 
of  cerebrum.  467 
interior,  512 
of  cervical  plexus,  38,  65 
of  digastric  triangle,  63 
of  dnra  mater.  711 
of  ear,  399 
of  eyeball,  357 
of  face.  625 

incision,  597.  623 
of  lilirous  coat  of  eye,  :!61 
of  lacrvmal  apiiaratus,  351 
of  larynx,  248 
of  lateral  ventricles,  518 
of  lingual  triangle,  64 
of  membranes  of  liiain,  707 
of  middle  car,  407 
of  mouth,  20i) 
of  ninscles  of  tongue,  108 
of  neck,  17,  26 
incision,  623 


Dissection  of  neck,  muscles,  48 
of  nose,  284 

of  occipital  triangle,  57 
of  orl)it,  360 
of  pliarynx,  227 
of  jions  Varolii,  549 
of  ptervgo-maxillary   region, 

676 
of  scalp,  601  ■ 
of  sulwlavian  triangle,  59 
of  submaxillary  triangle,  63 
of    supraclavicular     triangle, 

59 
of   temporal  region,  625,  621 
of  tongue,  216 
of  triangles  of  neck,  54 
Diverticulum,  esophageal,  26 

pharyngeal,  26 
Divisions  of  nasal  fos-saj,  300 
Dorsalis  lingua;  a.,  114,  105 

scapulae  a.,  133 
Double  chin,  17,  31 
Douche,  nasal,  308 
Dropsy  of  antrum   of    Highmore, 

315' 
Duct,  cochlear,  432,  437 
lacrymal,  352 

orifice,  355 
lacrvmo-na.sal,  352,  350 
Ivmphatic,  160 
nasal,  3,52,  594,  314 
orifice,  299,  298 
of  Bartholin,  114 
of  Meibomian  gland,  353 
salivary,  obstruction,  114 
StensoiVs,    658,     608,    613, 
621,  627,  640 
course,  658 
divisions,  buccal,  659 

ma.sseteric,  659 
line,   27,  623 
relations,  (i,"i8 
thoracic,  128,  160,  129 

relations,  131 
thvro-glossal,  125,  216 
Wharton's,  113,   70,   71,    78 
relations,  113 
Ducti  Rivini,  114 
Ducts,  lacrymal,  orifice  of,  653 
of  Meibomian  gland,  648 
orifice,  653 
Ductus  endolvmphaticus,  431,  437, 

439 
Dura  mater,  of  brain,  708,  709 
attachment,  711 
blood  supply,  726 
dissection,  711 
havers,  711 
nerve  supply,  726 
processes,  717,  714 
pulsivtions,  711 
sarcoma,  711 
sinuses,  718,  715 

hemorrhage 
from,  719 


E. 

Earache,  407 

E;vr  cough,  81,  407 

dis.siclion,  399 

external,  399,  601,  660,  405 


Ear,  external,  arteries,  665 
divisions,  660 
muscles,  665 

extrinsic,  605 
intrinsic,  665,  663 
pinna,  660,  661 
landmarks,  701 
internal,  399,  431 

blood  su])ply,  437 
lymphatics,  438 
veins,  437 
labyrinth,  bonv,  430,  427 
middle,  399,  407,  405 
blood  supply,  425 
disease,  420 
dissection,  407 
inflation,     Pol  itzer's 
method,  411 
A'alsalva's   method, 
411 
lymphatics,  425 
pyramid,  412 
veins,  425 
Edema  of  glottis,  269 
Eighth  cervical  n.,  149 

anterior  division, 79 
cranial    u.,    456,    458,    542, 
556,    715.     Viile 
Auditory  Nerve, 
origin,  552 
Ejaculator  seminis  m.,  604 
Elevation  of  cornea,  348 
Eleventh  cranial  n.,  57,  466,  729, 
458,    542,    556, 
715 
origin.  552 
Eminence  frontal,  591 
Eminentia  collateralis,   495,  531, 
519,  523 
teres,  547.  536,  542,  556 
Emmetropia,  395 
Emmetropic  eye,  388 
Emphysema  of  orbit,  323 
Empyema   of    antrum   of  High- 
more,  312 
of  frontal  sinus,  311 
Encephalocele,  591 
Enoephalocelcs,  sincipital,  286 
Encephalon,  455.      Vide  Brain. 
Endolymph,  431,  432 
Entropion,  361 
Enucleation  of  eyeball.  396 
Epiglottis.  2711.  123,   218,    236, 
250,251,254,258,259. 
267, 296 
action,   270 
tubercle,  270 
Epilepsy,  .lacksonian,  trephining, 

504 
Epiphysis    cerebri,     528.         Vide 

Pineal  Body. 
Epistaxis.  :!oi,  613 
Eiiithclioma  of  nose,  285 
Equator  of  eyeball,  357 
E<inilibrium,  maintenance,  432 
Ergot,  531 
Erysipelas,  616 

Esojjhageal    branch     of     inferior 
thyroid  a,,  145 
diverticulum,  25 
EsopliagoTonn'.  226 
Esophagus,  226,  39,  41,  129,  236 
nmscles,  229 


JAJ)KX. 


747 


Es()i)lm<;Hs,  rolatioiis,  ^26 
Ktlmioiil.  291 
iii'tciT,    '■"■i7 

aiitiiidi-,  :i()7,  .'!:!T.  334 

brancliis.  .'i.'iT 
posterior,   :«I7.  S:!?,  334 
colls,  31.-),  321 
simiscs.  ;{1.").      l'i<li    I'^tlinioid 
tVlls. 
Eustacliiiin  tube.  1(H.  243,  405, 
409 

Ijlc.od   Sll))|llv,      II'J 

nuicoiis  ^l;imls.    Ill 
nerve  sujiply,   II'J 
(welusioii.   111 
oiilice,  •2:a,  298,  422 
relations,  41 1 
Evisceration  of  the  eyeball,  HiKi 
Excision   of   condyle   of   inferior 
maxilla,  o-^l 
of  eyeball,  I5!H> 
of  inferior  maxilla,  5><I5 
of  larynx,  'J81 
of  superior  maxilla,   line  of 

incision,  572 
of  tonftnc,  223 
of  n]i])er  jaw,  .579 
Exenteration  of  orbital  contents, 

3SIG 
Exophthalmos,  3.57 
Expres.sion,  facial,  596 
External  anditorv  canal,   1(13 

capsule,  548,'  546,  565,  569 
ear,  399 

lateral  ligament  of  temporo- 
maxillary  articulation,  574 
Extradural  abscess,  423 
trephining,  ."jH 
hemorrhage,  711,  733 
trephining  in.  734 
Extrinsic  m.  of  tongue,   109 
Eye.      J'icle  Ejehall. 

chamber,  anterior.  3!ll,  360, 
369.  394 
angle.  391 
sinus.  391 
posterior.  392,  394 
vitreous,  385,  360 
chambers,  391 
coats.  .361,  369 
dangerous  area.  368 
emmetropic.  388 
enucleation.  396 
evisceration.  396 
excision,  396 
hyperopic,  389 
landniark.s,  593 
lymi^h  pa.ssage,  anterior,  392 

posterior,  392 
myci]iic,  389 
refracting  media,  361 
section,  360 
va.si'idar  coat,  367 
Eyeball,  3.")7.  330,  334,  649 
axis.  3.57 

blood  vessels.  384 
chamber,  .uiteiior.  391.  360, 

369.  394 
ciliar.v  region.  36-*.  372 

section.  365 
eoate.  361.  369 
diameter,  .sagittal,  357 
transverse,  357 


Eyeltall,  diameter,  vertical,  357 

dissection,  3.57 

ei|uatoi',  3.57 

inlliilion,  318 

lymphatic  system,  392 

mobility,  3.57 

pole,  anterior,  3,57 
pc)Sterior,  357 

sinUing,  3.57 

snsjjcnsory  ligament,  324 

veins,  379 
Eyebrow,  648 

muscles,  630 
Eyelash,  353 
Eyelashes,  648,  651 
E.vclid,  section,  .sjigittal,  353 

skin,  353 
Eyelids,  352,  618,  652 

areolar  tissue,  652 

blood  sujiplv,  655 

lympliaties,  655 

nuistdes,  630 

nerve  ,supi>l.v,  655 

veins,  655 


Face,  absces.s,  626 
appearance,  592 
arteries,  596,  608,  613,  640 
boiu-s,  fracture,  586 
dissection,  625 

incision,  597,  623 
fascia,  snperfieial,   6'.'6 
incision   for  dissecting,  597, 

623 
landni.'U'ks,   592 
l,vm])liatics,  703 
liiuscles,   626,  613,  627 
nerves,  691,  609,  613,  620 
skin,  625 

surface  markings,  592 
va.scularity,  617 
veins,  35!  645 
vvonnds,  (i  17 
Facial  a.,   9-.'.  63-*,   50.   70.   78. 
79.   105.    133.    608, 
613.  620.  621,  640 
anastomosis,  648 
branches.  6-13 
cervical  jiortion.  92 

l)ranches,  92 
course,  ().38 
irregularities,  190 
ligation,  190 
line    for,     20,    27,     67, 

623 
o]ieration  to  expose,  182, 

183 
relations,  638 
transverse,     61 1.      608, 
613.   620,    640, 
678 
anastomosis,  644 
expression.  596 
monoplegia.  .504 
nerve,   li;5,  666,  7--'-<.  51.  71, 
78.     79,     203     539, 
620,  621.       1 7(/c  Sev- 
enth f'ranial  Xerve. 
anricularis  magnus,  38 
branches,  666 


Facial  uerve,  huccnl  branch,  669, 
609.  613,  620 

eoui'se,  (!66 
digastric  branch,  669 
divisions  of.  facial,  (>66 
intra-cranial,  Ii66 
teiniioral,  6<)6 
iuframaxillarv      branch, 

34,  620 
infra  orbital     b  r  a  n  c  h  , 

609,  613,  620 
line  for,  20,  27,  67 
malar      braiieh,       609, 

613.  620 
operation  to  expose,  666, 

203 
paral,\sis,  670 
stretcliing,  2(15 
st,vlo-liyoi<l   branch,   669 
sui)ra-m,'ixillarv   bran<'li, 
67(1,  609,   613.  620 
tem)ioral      biaiieb.     (112, 
609,   613,   620 
vein,    93,    644,   35,    50,    70, 
613    620.  621,  645 
arterial  Ijlood  in,  (147 
communications,  647 
course,  647 
deep,  ()87 

di.seases  involving,   647 
line,  623 
relations,  93,  647 
tran.sverse,  35,  645 
Facies  Hipjioeratica,  593 
Falx  cerebelli,  717,  71.^  714 

cerebri,   512,   712,    717,   718, 
714 
Faradization  of  diaphragm,  155 
Far-sightedness,  363 
Fascia,    bucco-pharyngeal,     213, 
226 
cervical,  deep,  45 
course,  -16 
di.'igram,  41 
deep,  of  neck,  34 
dentata,  496,  .531,  536 
orbital,  323,  320.  321 

lamina,  323 
parotid,  .520 
pretracheal,  47,  39,  41 
prevertebral,  4(1,  39.  41 
salpingo-pharyngeal,  408 
superficial,  of  face,  490 
of  neck,  26 

of  scalp.  602,  599,  603 
temporal,   618,  620 

abscess  beneath,  618 
density,  618 
relations,  (iI8 
Fat,  orbital,  323,  326,  330.  632 

foreign  body,  32!i 
Fauces,  istlninis,  213,  224,  237 
pillar,    anterior,    212,   218, 
250 
jiosterior,       212,       218, 
236.  250 
pillars,  221 
recess.  224 
Fenestra  ovalis.  420.  427 

rotunda.  420.  427 
Fever  blister.  210 
Fibers,      arciform.       superficial, 
554 


748 


INDEX. 


Filji'o-cartilage,  iiiterarticular,  of 
teinporo-maxillary  articulation, 
574 
Fibrous  coat  of  eye,  361 

ilissectiou,  3G1 
Fifth  cervical  n.,  149 

anterior       division, 
39,  71.  78 
cranial   u,    41).'),    326.    339. 
458.  542.  556 
oplitlKilinii^     (1  i  V  i  - 

sioii,  326 
origin,  552 
nerve,  .539,   675,   728,    695, 
715 
branches,  675 
ventricle,    525,     497,    516, 
523. 565 
Filiform  papilla",  219 
Fillet,  543,  539 
Filtration  angle,  3!)1,  394 
Fimbria,  526 
First  cervical,  u.,  727,  539 

cranial  n.,  461.      Vide  Olfac- 
tory Nerve. 
thoracic  n.,  anterior  division, 
79 
Fissura  palpebrarum,  648 
Fissure,  calcarine,  475,  4!H,  488, 
494,  497,  516 
callo.sal,  41)6,  488,  497,  516 
calloso-marginal,      !7(),     4^9, 
496,  474,  477,  480,  497, 
516 
central,   475.       Vide  Fissure 

of  Kolando. 
collateral,  495,488,494,497 
dentate,  496 

frontal,   inferior,    4R1,    474, 
477,  480 
line,  .5(18,  506 
superior,  4H1,  474,477, 
480 
line,  .508,  506 
hippocampal,  496,  488,  494, 
497,  536,  569 
pi.i  mater,  546 
horizontal,  of  l)rain,   467 
hypoglossal,    554 
intra -parietal,      485,     474, 
477,  480 
line,   509 
longitudinal,   459,  480 
line,  ,507,  506 
of  brain,  467 
median,  longitudinal,  544 

posterior,  542 
occipital,  inferior,   490 

middle,  490,  477,  480 
posterior,  lini-,  506 
superior,  490,  477,  480 
transverse,       190,      477, 
480,  572 
of  anus,  591 
of  Bichat,  467,  532 
of  cerehclluni,  great  horizon- 
tal, .561,  560 
superior,  .561 
of  helix,  400,  r,m 
of   medulla  oblongata,    ante- 
rior  median,  .553, 
552 
postero-median,  553 


Fis,sure   of    llolaiuln,    475,    474, 
477.  480.  516 
line,  .507,  506 
of  18antorini,  666,    401,  663 
of   Sylvius.    456,    470,    471, 
474,  477,  569 
line,  507,  506 
olfactory,  456,  4s2.  488,497 
orbital, "456,  482.      Vide   Tri- 

radiate  Fissure. 
palpel)ral.    593,  649 
paracentral,  489,  488,   497, 

516 
parallel,  492,  477 
parietal,  572 

parieto-oecipital,     475,    474, 
477,  480,  488,  494, 
497,  516 
line,   .508 
post-central,  485,  474 
post-olivary,  554 
precentral,'  481,    474,    477, 
480 
line,    508 
sphenoid,  nerves  in,  342 

structures      tiaversing, 
343 
subparietal,   489,    496,    488, 

497,  516 
temporal,      middle,     474, 
477 
superior,  474 
temporo-splieniiid,      inferior, 
492,  488,  494,    497 
middle,  492,   494 
line,  510,  506 
superior,  492,  494 
line,  510,  506 
transverse,    467,    481.       Vide 
Fissure,  Precentral. 
line,  507 
triradiate,     4.56,     482,     458, 
483,    488,     497.        Vide 
Fissure,  Orbital. 
Fissures,  cerebral,  lines,  589 
of  brain,  lines,   506 
of  cerebrum,  468 
complete,  469 
incomplete,  469 
primary,  470 
Fistula,  auricular,  400 

salivary,  659 
Fistulie,  cervical,  congenital,  25 

l.nchrymalis,  311 
Flocculus  of  cerebellum,  .562 
Floor  of  fourth  ventricle,  536 
Fluid,  eerebro-spinal,   442 
Fold,   arvteno-epiglottidean,  248, 
2i8,  250,  258,  259 
glosso-epiglottidean,216,218 
lateral,  216,  250 
nudiai),  216,  250 
interarytenoid,  218,  250 
Folds,  aryleno-epiglottidean,  248 

of  membrana  tympani,  419 
Folium  e.acuminis  of  cerebelhnn, 

.561,  560 
Fontana,  .spaces,  362,  392,  365 
Fontanel,  anterior,  584,  588 
antero- lateral,  584 
posterior,   584,  588 
postero-lateral,  584 
Fonticulus  gutturis,  18 


Foramen  caecum,  216,  218,  236, 
250,  715 

commune  anterius,   537 
infra-orbital,  595,  699 
magnum,  structures  travers- 
ing, 461 
magnum,  superior,  718 
mental,  595 
occipital,  superior,  718 
of  Key,  441,  544 
of  Ma'gendie.  441.   .544 
of  Momo,  51K,  .537.  516,519, 

528,  529 
of  Ketzius,  441,  544 
of     spheiiD-nia.xillary     fossa, 

693 
pterygo-  palatine,  693 
rotu'ndum,  693,  309 
sderie,   361 
spheno-jjalatine,  693 
superior  occipital,  718 
supra-orbital,  595 
Forceps  minor,  517 

major,  517 
Foreign  bodies  in  brain,  511 
body  in  orliital  fat,  323 
Foreskiii,  628 
Formatio   reticularis,     550,    553, 

483 
Fornix,    ,522,    488,    497,     516, 
523,  569 
body,  522,  533,  546 
buliis,  460 
oonjunctivie,  320 
Ijillar,    anterior,     .522,    516, 
529.  533,  536,  542, 
546,  556 
posterior,  522,  523,536, 
546 
Fossa,  digastric,  591 
innoiuinata,  269 
lacrvmal,  316 
of  aiitihslix,  339,  660,   398, 

661 
of  helix,  339,  660,  398,  661 
patellar,  385 

pituitary,  diaphragm,  717 
scaphoid,  of  ear,  660 
scaphoidea,  399 
sphenomaxillary,  693 
contents,  693 
foramina,  ()93 
supra-clavicular,  18,  21 
supraclavicularis   minor,   18, 

21 
supra-sternal,  18,  21 
zygomatic,  693 
contents,   693 
Fossre,  nasal,  294 

anterior  view,  306 
di\  isions.  300 
lymphatics,  307 
mucous  membrane,  309 
olfactory  portion,  300 
posterior  vie^v,  309 
respiratoiy  portion,  300 
Fourth  cervical  n..  anterior  divi- 
.sion,  71.  78,  149 
cranial    n.,    327,    462,    326, 
339,    343,    458, 
542,    556,    560. 
Vide     Pathetic 
Nerve. 


IXDEX. 


749 


Fourth  cranial  n.,  orifjiii,  552 

riTuiiviit    l)rancli, 
326 
nerve,  728,  715 
veiitrii-li\    .">ll.     516,     528, 
529.  560 
111).)!-,  536 
Fovea  centralis,  :!■<() 
infirior,  .">1T 
liciniolliplicn.    1:M,  430 
lirmispli.ii.-.i,    I:>1,  430 
su|it'ii(>r,  .")  17 
Fractuie  into  frontal  sinns,  :?11 
of  lioni's  of  fact".  .)^() 
of  liyoiil  lioiie,  ■J.'^l 
of  iiilVrior  maxilla.  .">■<(>,  581 
of  lanvMial  bono.  ,58(> 
of  na.sal  liont's,  "JSli,  586 
of  skull,  584 
base,  58,5 
vault.  585 
of  supciior  maxilla,  .586 
of  tliyroiil  i-artilajic  '274 
of  zy^omatif  arch,  .5'<6 
Fractures,    c-ompouud,    of  skull, 
707 
of  skull,  base,  692 
Fnenuin  epi^lottidis,  316 
labii  inferioris,  210 
superioris,  210 
Frenulum,  541! 
veli,  560 
Frenuni  of  tongue,  215 

artery,  115,  105 
Frontal  a.,   :«7,  60(;,  603,  608, 
613,  620,  640 
anastiouiosis,  31!7,  600 
a.scending,  447 
inferior,  447 
bone,  .sinuses,  591 
branch   of  anterior  ethmoid 

a.,  H:!7 
convolution,  ascending,   482, 
474,  477,  480 
inferior,  482.  474,  477, 

480 
middle.  482.   474,  477, 

480 
superior,  482,  474,  477, 
480 
diploic  v.,  707,  705 
eminences,  591 
fissure,    inferior,    4-*!,    474, 
477,  480 
line,  50^,  506 
superior.  4-<l,  474,  477, 
480 
line,  508,  506 
lobe,  456,  475,  481 

inner  surface,  485 
landmarks.  508 
orbitid  surface,  482 
lymphatics.  615 
lierve.    :!27.    326.   339.  343 
sinus,   :',ii-,   298,  314.  339, 
355 
coMfiiestion,  311 
empyema,  311 
fracture.  Mil 
polvpus.  311 
pus.  311 
sinuses,  653,  705.  709 
suture,  573,  588 


Frontal  vein,  35,  645 
Frontalis   m.,    (115,    627.       Vide 

( )eei])it<i-fioiUalis  Muscle. 
I'voiito-siilienoiil  diploic   v.,    707, 

705 
Krost-liite  of  pinna,  400 
FnuKiform    i)apill:e,     219,     218, 

250 
FuiiKUS,  648 

Funicnhis    e\iMeatus,      .554,    5.57, 
536,  542.  556 
gracilis,  554,  557,  536,  542, 

556 
of  Kolando,  554,  .557 
FiHM'ow,  branchial,  2(t 

of   medidla    oi)longata,    an- 
tero-lateral,  551 
Furrowed  band,  562 
Fusiform  I'onvolution,    495,  488, 
494,  497 


Galen,  vein,  714 

veins,  4  12,  .5.32,  533 
Ganglia,  cerebral,   anteiior.   ,525. 
l7(/<'  Corpus  Striatum, 
posterior,     526.       V  i  il  e 
Optic  Thalamus. 
of  pneninogastric  n.,  76 
Ganglion,  Arnold's,  691 

ciliary,  ;>38.     Viih-  Ganglion, 
Lenticular, 
branches,  341 
Ga-sserian,    730,    326.   339, 
695,  715 
brauclies,  730 
relations,  730 

to   cavernous  sinus, 
725 
renuival,  731 
resection,  199 
intercarotid.  7(i 
jugular,  IKi 

lenticular,    338,    326,    339, 
I  'iili-  (iangi  ion,  Ci  I  iary . 
sensorv  root.  :'>35 
Jleckel's,  '697,     303,    686, 

690 
of  Andersch,  116 
of   synipathetic  cervical,   in- 
ferior. 85 
middle.  84 
sn]>erior.  84 
ophthalmic.  :i38 
otic,  (i91,  303,  690 
petrous.  116 
s|iheno-])alatiiie,  697 
submaxilhiry,  113 
Ganglionica.,  antero-lateral,  444 
antero-niedian,  444 
poslero-median,  444 
Gangrene  of  pinna.  400 
Gas-serian    yilu^lion.    7:')0.    326, 
339.  695,  715 
branches,  730 
relations.  730 

to  cavernous  sinna, 
725 
removal.  731 
resection.  199 
Geniculate  liodies,  538 


Geniculate  bodies,  external,  538 
internal,  ,538 
body,    external.   463,    539, 
552 
internal,  463,539,542, 
552,  556.  560 
Gcnio-hvo  ;;lo>sii-!    m.,    111.   220, 
78.     79,     105,     109, 
212,  296 
action,  1 1 1 
blood  snppl\  ,111 
insertion,  1 1 1 
nerve  supply,  111 
origin,  1 1 1 
relations,  1 1 1 
Geuio-hvoid    m.,     1(17.    78,    79, 
105,    109,  212,  296 
action,  llH 
blood  sn]i|)ly,  107 
insertion.  107 
nerve  supjily,  107 
origin,  107 
Genu    of   corpus   callosum,     517, 

488,  497,  516    523,  564 
Gingival  a..  682,   695 
Glabella,  .507,  5,S8.  ,-,94,  506 
Gland,  lacrvmal,  653 

parotid',     656,       608,      613, 
627, 640 
contents,  657 
lobe,  carotid,  6.56 
glenoid.  6,56 
jitcrygoid,  (!56 
removal,  (i58 
sensorv  nerves,  657 
woiMids,  6.58 
Glands,  auricular,  posterior,  157 
buccal,  213.  638 
cervical,  deep,  157 

superlicial,  iw.  157 
infraclavicular,  157 
labial,  21(» 

lacrvmal,      323.    328,     326, 
330.  334,  339,  355 
inferior-,  32*-< 
sui)erior,  328 
sus])ensoiy  ligament,  328 
lymphatic,   auricular,   poste- 
rior, 7(r2 
buccal,  702 
lingual,  703 
ma.stoid.  702 
nuixillary,  internal,   703 
occijiital,  702 
of  head,  702 
parotid.  657,  702 
posterior  pharyngeal.  703 
submaxillary,  702 
sub(n-cipital,  702 
Meibomian,    5ii3,    652,   346, 
355,  632.  653 
duct,  353 
ducts,  (!ls 

orilice,  653 
molar,  213 

mucous,  of  Eustachian  tube, 
411 
of  larynx,  260 
of  nose,  302 
occipital.  157 
of  Blandiu.  219 
of  carotid  sheath.  73 
of  neck,  159,  157 


750 


IXDKX. 


Glands  of  Nuhn.  219 
of  tongue,  219 
parotid,  63,  157 
pineal,  539.        Vide    Body, 

Pineal, 
sebaceous,  of  oilium,  353 
sublingual,  113 

blood  supply,  114 
nerve  supply,  11-1 
relations,  113 
submaxillarv,   63,   103,   113, 
51,  157,  177 
relations,  U)3 
sweat,  of  Moll,  353 
thyroid,  23,    122,  123,  129, 
251 
arteries,  126 
capsule,  126 
in  tracheotomy,  122 
isthmus,  251 
nerves,  126 
relations,  122 
structure,  122 
Waldeyer's,  353 
Glaucoma,  395 

pa4n,  362 
Glosso-epiglottidean    fold,      216, 
218 
lateral,  216,  250 
median,  216,  250 
ligament,  270 
pouch,  216 
valleculfE,  216 
Glosso-pharvngeal  n.,    115,   116, 
466,729,79,539.  Tide 
Ninth   Cranial   Nerve, 
relations,  116 
tympanic  liranch,  426 
Glottis,  edema  of,  269 
false,  266 
respiratoria,  266 
vooalis,  266 
Goitre.      ]lde  Thyroid  Gland. 
Gracile  nucleus,  557 
Gracilis  funiculus,  557 
Great  horizontal  tissure  of  cerebel- 
lum, 2(!1 
Groove,  lacrymal,  317 
Guide    to  subclavian    a.,    third 
portion,  175 
to  vertebral  a.,  176 
Gum  boil,  214 
(Jums,  the,  214 
Gustatory  n.,  112,  688 
Gyri,  468.      Vide  Convolutions, 
annectant,  4.85 
operti,  of  island  of  Reil,  471 
Gyrus,  angular,  4h9 

fornicatus,   499,    488,    497, 

516 
rectus,  4S2,  483,    488,  497 

H. 

Hammer,  423.      Vide  Malleus. 

Handle  of  malleus,  418,  422 

Harelip,  21:;,  614 

operation,  210,  213,  644 
hemorrhage  in,  644 

Head,  arteries,  573 

lymphatic  glands,  702 
nerx'cs,  operations,  196 
of  caudati-  niicU-ns,  536 


Head  of  malleus,  422 

veins,  665 
Headache,  trephining,  512 
Hearing,  center,  5(i:! 

organ,  399 
Helicis  major  m.,  66.-),  401.   663 

minor  m.,  665,  401,  663 
Helicotrema,  432 
Helix,  399,  660,  398,  401.  661, 
663 
fissure,  40(1,  (i66 
fossil,  399,  (iCO.  398,  661 
Hematoma  of  scalji,  617 
Hemianopsia,  4()2,  5U4 
Hemiplegia,  504 
crossed,  550 
Hemispheres  of  cerebellum,  461 
Hemorrhage,  cerebral,  a.  of,  446 
extra-<Uiral,  711,  733 

trephining  in,  734 
from  artery  of  septum,  643 
from  nose,  301 
from  sinus  of  dura,  719 
in  operation  for  har<*lip,  644 
into  pons  Varolii,  ^>M) 
into     pterygo-maxillary     re- 
gion, 692 
subconjunctival,  358 
Herpes  cervico-occipitalis,  45 

labial  i.s,  210 
Hiatus    semilunari.s,    209,    298, 

314 
Highmore,  antrum  of,  312,  339. 
350 
abscess,  312 
cysts,  315 
dropsy,  315 
empyema,  312 
mucocele,  312 
oritice,  298 
tumors,  312 
Hippoc,am|iaI     convolution,     495, 
488,  494,  497 
fissure,  4!m;,  488,  494,  497, 
536,  569 
j)ia  mater,  546 
Hippocampus    nuijor.      19('>.     526, 
519,  523,  529,  536,  546 
minor,    191.   521,    531,    519, 
523,  529 
His,  canal,  125 

Horizontal     division     of     lateral 
siuns,  720 
fissure  of  brain,   467 
Horner's  ni.,   633.      Vide  Tensor 

Tarsi  Muscle. 
Horny  band,   526 
Huguier,  canal,  691 
Huuu)r,  ai|Ueous,  ,392 
Hutchinson,  test  teeth  of,  214 
Hvaloid  artery,  385 
canal,  Ssii,  392 
membrane,  i!i^5 
Hydrocephalus,  internal,  442 
Hyo-epiglottidean  ligauu-nt,  270 
Hvo-glossusm.,  lOS.  220,  78,  79, 
105,  109.  177 
action,   10>< 
blood  supply,  108 
insertion,  lO.'^ 
nerve  suiiply,  108 
origin,   108 " 
relation,  108 


Hyoid  a.,  86 

bone,  23,  281,  109,  123 
fracture,  2isl 
Hypermetroi>ia,  3(i3,  373,  395 
Hy])eropia,   395 
Hyiieropic  eye.  389 
llvpertrophy  of  iiliarvngial  tonsil, 

232 
Hypo-glossal  fissure,  554 

membrane,  21(i,  220,  270 
nerve,    104,    112,     177,    467, 
.554,  729,   51,  71,  78, 
79,539.   1 7</r  Twelfth 
Cranial  Nerve, 
paralysis,  104 
relations,  104 
Hypopyon,  392 

I. 

Incision  for  abscess  of  parotid,  658 
for  dissection  of  face,  597, 
623 
of  neck,  623 
for  expo.sing  facial  n.,  672 

infra-orbital  n.,   699 
for  larvngotomy.  21 
for  tracheotomy,  21 
Wilde's,  591 
Incisive  a.,  683,  682 

branch  of  mvlo-hvoid  n.,  691, 
695 
Incisura  cerebelli  anterior,  561 
posterior,  561 
intertragica,   399,  660,  398, 

661 
mar.supialis,  561 
Santorini.  JOi! 
thvroidea',  254,  271 
Incus,  42:!,  405,  409,  413,  422 
caries,  424 
ligament,  424 

posterior,  422 
long  process,  418 
OS  orbiculare,   424 
Inferior  condyle,  excision,  584 
maxilla,  excision,  583 

fracture,  586 
obliciue  m.,  339 
Inflammation  of  scalp,  617 
luflation  of  eyeball,  318 

of  middle  ear,  Politzer's  me- 
thod, 411 
Valsalva's    method, 
411 
Infraclavicular  lvn\i)hatic  gland, 

157 
Infra-hvoid  a.,  >^6,  50,  70 

vein,  117 
Infra-marginal  convolution,  462 
Infra-maxillary  branch  of  cer\  ico- 
facial  n. ,  45 
of  facial  n.,  670,  34,620 
Infra-orbital  arterv.  67(i,  (;s-l,620, 
678,   682,   686,  695 
anastomosis,  ('<',(', 
branch  of  lai-ial  n.,  (;69.  609, 

613.  620 
foramen,  595,  (;!)9 
margin,  316,  ,594 
nerve,   675,   697,   609,    620, 
695 
liranches,  675.  Cl'T 
labial,  <::.">,  620 


L\DEX. 


751 


Infra-orbital   iiervo,    hranolips, 
nasal,  (!*."),  620 
l>aliu-l)ial,  1)75,  620 
openitiiiii   to  oxpose,  (i!)!! 
stnii'tinv    iiivolvt'il, 
()!l!) 
resection,  19!) 
plexns  of  nerves,  (jG9,  675 
vein,  (>~(> 
Infnirimal  imrtionof  larvnx,  296 
Inlra-tr(M-liKar  n.,  :!3.'i,  326,  609, 

613.  620 
Infiindihiilifonn  fa.scia,  (il3 
Infiindlliiiliiiii.  539 
Inion,  .■)lll,  506 
Injinies  of  ni'cU,  '^\ 
Innominate   a.,    78,    129.    133, 
164 
bifuiciition,  70.  78 
guide,  Kill 
irreaularities,  l(i6 
lig-.vtion,  KiO,  1(J5 

collateral       circula- 
tion, lG,j 
line,  20 

operation  to  exix)se,  164 
puls;itions.  18 
relations.  Icio 
vein,  35,  645 
left,  129 
ri-lit.  129 
Internment  of  anriele,  400 
Interartienlar     til  iro-cartilage    of 
temporo-niaxillary  articnlation, 
574 
Interarvtenoid  fold,    218,    236, 
250 
ganglion,  71! 
Intercostal  a.,  133 
tirst,  147 

superior,  147,  133,  137 
nerve,  first.  149 
Intercrnral  space,  459 
Internal  e^Tpsule,  547,  565,  569 
genu,  548 
liemorrliage.  548 
limli.  .-mterior,  547,  546 
posterior,  547,  546 
ear,  :5nii,  4:U 

blood  supply,  437 
lymphatics,  438 
veins,  437 
lateral  ligament  of  temporo- 
maxillary  articulation,  574 
maxillary  v.,  35 
Interpeduncular  space,  459 
Intei'stitial  keratitis,  3(32,  363 
Intersutural  membrane,  1117 
Intervaginal  lymjih  space,  395 
Intra-cranial  abscess,  511 
division  of  facial  n.,  666 
nerves.  727 

coni-se.  727 
neurectomy  of  inferior  maxil- 
lary n..  730 
of  superior  maxillary  n., 
730 
Intraparietal   fissure,   485,   474, 
477. 480 
line.  509 
Intrinsic  ni.'s  of  pinna,  40O,  401, 

663 
Irido-cyclitis,  374 


Iris,  the,  .iiC.   360,    365.    369, 
376.  394 

absence,  31)8 
blood  supply,  368 
(•left,  368 
color,  367 
crypts,   392 
lymi)h  spaces,  392 
nerve  supply,  368 
jiectinatc  ligament,  364 
rellex,  368 
Irregularities  of  carotid  a.,  inter- 
nal. 196 
of  occipital  a.,  195 
IrritJition   of  laryngeal  n.,  supe- 
rioi",  >'2 
of  lingual  n.,  223 
Island  of  Keil,  470,  481,  .548,  471, 
483,   546,    565,  569 
gvri  (iiiirti.  471 
Isthmus,    ino.  488.  494.  497 

of  ra\K-rs.  -.'i:;,  221,  237 

(if  thvn)id  gland,  251 
tnb;c.  411 
Iter  chord:e  anterius,  691 
posterins,  412 
e  tertio  ad  ciuartum  vcntric- 
ulum,  51s,  .537.    Vide  Aque- 
duct of  Svlvius. 


Jack.sonian  cpilejjsy,  trephining, 

504 
Jacobson's  n.,  116 

organ,  300 
.Taw,  lower,  dislocation,  579 

upper,  excision,  579 
Joints.      J'ide  Aiticulatious. 
Jugular  ganglion,  IK! 

vein,  anterior,  2!!.  37,  30,  34, 

35.  39.  50,  70,  117, 

174,  177.  645 

external.  32.  60.  30,  34, 

35,    39,    50.    70, 

174.  208,  645 

jugulo  -  c  e  ])  h  a  1  i  c 

liranch.  23 
line.  23,  32,  27,623 
pnlsiition,  32 
termination,  18 
internal,  61,  62,  73,  35, 
39,    41,   50,   70, 
78      129,     164, 
174.  645 
jMisition.  Is 
relations.  73 
posterior.    30,    50,    70, 
208,  645 
extiTual,  :!7 
Jngnlo-cephalic  branch  of  exter- 
nal jugular  v.,  23 


Keratitis,  intei-stitial,  362,  363 
Keratosis  senilis,  593 
Key,  foramen,  441,  544 

L. 

Labial  a,,  inferior.  643.  608.613. 
640.  682 
anastomosis,  643 
branch    of    nifra-orbital    n., 
675,  697,  620,  695 


Labial  glands,  210 

vein,  inferior,  117 
Labyrinth,    :!99.     131.       ('/(/(    In- 
ternal Ear, 
bony,  431 

external  view.  427 
internal  view,  430 
mendiranous,   l!!l,  432 

diagram,  439 
vestibule,    l:!l 
Lacrymal   api)arijtus,    liol,    350, 
355 
dissection,  l'>51 
artery,  323,  336,  334 

branches,  33(5 
bone,  frac^tiu'e,  586 
canal,  3,52 
canal iculi,     351,     648,    355, 

653 
canaliculus.  350 
caruncle,  649 
duet,  352 

ducts,  orilice  of,  355,  653 
f(>S!-a,  316 

gland,   323,   328,   326,  330, 
334.  339.  355.  653 
infeiior,  32-< 
.superior,  328 
sus))en,sory  ligament,  328 
groove,  iil7 
nerve,    :!23,    327,   675,   326, 

339,  343 
ptmctum,  649 
Siic,     352,    ,591,     321,     350, 
355,  653 
abscess.  ()44 
Lacrymo-nasal  duct,  3,52,  350 
Lacuna'  lateralis,  719 
Lacus  lacrvnialis,  648 
Lambda,  .57:'.,  588 
Landxloid  suture,  .573,  588 
Lamina  cinerea,  459,  516,  565 
cribrosii,  3(il,  362 
fusca,  ,362 

of  orbital  fascia,  323 
qnatlrigeniina,  537,  513 
spiralis,  432,  430,  434,  436 
siii)rachoroidca,      362.      374, 

369 
vitrea,  374 
Lamina'  of  cerebellum,  .558 
Lamin.ated    tubercle  of    cerebel- 
lum, 562 
Lancisi  n.'s,  517 
Landmarks,  cranio-cerebral,  499 
of  .luricle,  601 
of  cerebrum,  46S 
of  cranium,  587,  589 
of  ear,  701 
of  eye,  593 
of  face,  .592 
of  frontal  lobe.  508 
of  limbic  lobe,  499 
of  ne<'k,   17 
of  ncei|)ital  lobe,  509 
of  ])ariet.al  lolie.  .509 
of  pinna.  701 
of  tem]X)ral  lobe,  569 
of  temi)oro-siihenoid  lobe,  .509 
Laryngeal   a.,    inferior,   145.  265, 
263 
superior,  91,26,5,  50,70. 
78.  123,  251,  263 


r52 


INDEX. 


Laryngeal  asthma,  262 

"braiK-h  of  inferior  thyroid  a., 
145 
nerve.  123 

external,    2G2,    51,    71, 

78,   79,  177 
inferior,  W 

inteinal.    262.    51,    71, 
78,    79,     177,     251, 
263 
recurrent,  82.  127,  262, 

71,  78,  263 
superior,  62,  81,  262 
irritation,  82 
]iaralysis,  82 
pouch,  269 
sac,  269 
Laryngismus  stridulus,  262 
Laryngo-pharynx,  227,  212,  296 
Laryngoscopic  exiiiiii nation,  276 
Laryngotoniy.   2-<l,  279 

incision,  21 
Larynx,  217,  251 
apertnre,  218 

superior,  237,  247,  250 
arteries,  263 
blood  supply,  265 
cartilages,  270,  271 
dissection,  247 
excision,  281 
joints,  276 

iufrarinial  portion,  296 
ligaments,  276 
lymphatics,  265 
movements,  24,  281 
mucous  glands,  269 
memlirane,  269 
muscles,  258,  259 
extrinsic,  262 
intrinsic,  262 
nerves,  262,  263 
paralysis,  262 
relations.  247 
section,  212 
sinus,  266 

suprarimal  portion,  296 
veins,  265 

ventriclf,  248,  266,  212,  218, 
250,  296 
Lateral  cartihige  of  nose,  287 
superior,  286 
lithotomy,  621 
sinus,  720,  714,  715 
course,  592 
divisions,  720 
line,  721,  723 
oiH-ration   to  expose,  510 
tliromlidsis,  511,  720 
trilnitaries,  720 
tract    of   mi'diilla  oblongata, 

.->54,  552,  556 
ventricU\     51H,     497,     516, 
523 
body,    51X,     519,    528, 

569 
o<irnua,  519 

anterior,   ,521,    528, 

546 
middle,  .521.  528 
posterior,  .521,  528, 
546 
dis.spction.  518 
tapi)ing,  511 


Lateral  ventricles,  518 
Lateralis  nasi  a.,  644 

anastomosis,  644 
Laxator  tympani  m.,  424 
Layers  of  cornea,  363 

of  dura  mater  of  brain,  711 
of  scalp,  601 
Lead  poi.soning,  214 
Leeching,  720 
Length  of  neck.  17 
Lens,  386.  360,  372,  394 
capsule,  381 
cortex,  391 
crystalline,   386 

relations,  386 
nucleus,  391 
substance,  391 

suspensory    ligament,     385, 
360,  372,  394 
Lenticular   gaiiulion,    33S,    326, 
339 
sensory  root,  335 
nucleus,  .525,  548,  546,  564, 
565,  569 
Lenticulo-striate  a.,  446 
Leukoma,  364 

Levator  anguli  oris  m.,  636,  627 
action,  636 
insertion,  636 
n. -supply,  636 
origin,  636 
anguli  scapula'  m.,  39,  50, 

71,  152 
glandul;c  thyroidea;  m.,  122, 

123.  251 
labii  inferioris  m.,  636 
action,  6,36 
insertion,  636 
nerve      supply, 

636 
origin.  636 
snperioris    alajque    nasi 
m..   629, 
627 
action,  629 
insertion, 

629 
nerve   sup- 
ply, 629 
origin,   029 
rel  a  t  i  o  n  s, 
629 
muscle,  635,  627 
action.  635 
insertion,  635 
nerve      supply, 

635 
origin,   635 
relations,  635 
menti  m.,  627.      Vide  Leva- 
tor Labii  Inferioris  Muscle, 
palati  m.,  245,  242,  243 
action.  245 
insertion.  245 
origin,  245 
palpebriE  ni.,  339 

snperioris  m..  !!20,  6,55, 
320,  326,  330, 
334,  353,  355, 
653 
action.  331 
insertion,  328,  634, 
655 


Levator   ])alpel)ra!   snperioris 
muscle,  nerve 
supply.  331 
origin,  328,  6.55 
relations,  6.56 
Ligament,  capsular,    of  crico-ary- 
tenoid  articulation, 
276 
of     temporo  -  :naxillarv 
aiticulation,  ,573,576, 
577 
of  tympanum,  425 
check,  external.  324.  321 

internal.  324.  321 
crico-arytenoid.  ]iosterior.  276 

transverse,  276 
external  lateral,   of  temporo- 
m  a  X  i  1 1  ary  articulation, 
574 
glosso-epiglottidean.  270 
liyo-epiglottidean,  270 
internal  lateral,   of  temporo- 
maxillary   articu- 
lation. 574 
of    lower   jaw,    679, 
678,  686 
tarsal,  6: 11 1 
in  tympanum,  424 
of  incus,  424 

posterior,  422 
of  malleus,  anterior,  424 
external,  424,  409 
internal,  424 
superior,  423,  424 
suspensory,    424,     409, 
422 
of  Zinn,  347.  334 
orbito-tai-sal.  652,  320,  321. 

Vide  Septum  Orbitale. 
palpel)ral.  6.52 
pectinate,  of  iris,  364 
pterygo-maxillary,  231,  229 
splieno-mandibular.  .574 
stylo-hyoid.  115,  576,  577 
stylo-mandiliular,  .574 
stylo-maxillary,    46,  63,  574, 

'576,  577 
susi»nsory,  of  eyeball.  324 
of  lacrvnial  gland,  328 
of  lens.  385.  360,    372, 

394 
of  malleus,  413 
thvro-arytenoid,  superior, 

266 
thyro-epiglottidean,  270 
thyro-hyoid,    2.55,  254,  263 
Ligaments  of   crioo-arytenoid  ar- 
ticulation. 276 
of  larynx.  276 
of  pinna.  40(1 

of  temporo-maxiliary  articu- 
lation, ,573 
Ligamentum  jugale,  270,  275 

nucha',  '25.  39,  41 
Ligation  of  arteries  of  neck,  160 
of  carotid   arteries,  common, 
179 
collateral  circu- 
lation,     185, 
133 
arterj',  external,  186 

collateral  circu- 
lation, 187 


INDEX. 


753 


Ligation  of  wirotid a.,  internal,  10.") 
collateral  circula- 
tion,  I'JG 
of  facial  artery,  1!)() 
of  innominate  a.,  KiO,  Kio 

collateral,  circula- 
tion,  Ki") 
of  lin;;nal  a.,  lil,  ls<,  177 
of  occipital  a.,  !>l,  l!l.'> 
of  subclavian  a.,  V.Vi 

collateral       circula- 
tion, !:!.'>,  133 
first     portion,     115."), 

1()(> 
second  ])ortii)n,  lli.'i, 

\m 

third   portion,    16(>, 
l(i9 
collateral  circu- 
lation, 170 
of    temporal    superficial    a., 

1!).-) 
of  tlivroid   a.,    inferior,    145, 
179,  177 
superior,  l'<7,177 
of  vertebral  a.,  1415,  175 
Limbic  lobe,  landmarks.  499 
Line   for  bracbial  n.  plexus,  20, 
67 
for  carotid  a. ,    common,   20, 
27,  67 
external,  f«>.  20.  67 
internal,  20.  67 
for  dental  n.,  inferior.  20,67 
for  facial  a.,  20.  27,  67 

nerve,  20.  27.  67 
for    fissure   of   Kolanilo,  507, 
506 
of  Sylvius,  507.  506 
tor   frontal    fissure,    inferior, 
50.S,  506 
superior,  5tH,  506 
for  innominate  a.,  20,  67 
for  iutra-parietal  fissure,    509 
for  jugular  v.,    external,    23, 

3->,  27 
for  lingual  a.,  20.  67 
for  longitudinal  fi.ssure,   507, 

506 
for  occipital  fissure,  posterior, 

506 
for    parieto-occipital   lissure, 

50.y 
for  precentral  fissure,  508 
for  spinal  acces.sorv  n.,  20.  67 
for  .Steuson's  duet,  27 
for  snliclavian  a.,  20.  67 
for  temporo-spbiMiokl  lissure. 
middle,  510,  506 
superior,  510,  506 
for  thyroid  a.,  inferior,  20,67 

superior,  20.  67 
for  transverse  fissure,  507 
Keid's  ba.se,  507,  506,  589 
Lines  for    carotid  a.,    lonnnon, 
623 
for  connnon  carotid  a.,  623 
for  external  jugnlar  v..    623 
for  facial  a.,  623 

vein,  623 
for  li.ssures  of  brain,  506 
for  jugular  v.,  external.  623 
for  lateral  sinus.  I'i'i.  721 


Lines  for  longitudinal  sinus,  supe- 
rior, 7I!I 
for  sigmoid  sinus,  7'.!:>,  721 
for  Stenson's  duct,  623 
of  cerebral  fissures,  689 
Lingual  a.,  91,  114,  50.   70,  78, 
79,  105,  133,  177 
anast<)mosis,  1 1  1 
irregularities,  190 
ligation,  (54,  LSI,  177 
line  for,  20,  67 
operation    to    expose, 

183 
relations,  9"i 
branch   of  glosso-pliarvngeal 

n.,  119 
convolution,  495,  488,  494, 

497 
lymphatic  glands,  7015 
lierve,    11-3,    (i^M,    78,    202, 
678.  686,  695 
branches,  (iss 
irritation,  '^'XA 
o])eratioii  to  expose,  202 
relations,  Wi 
resection,  205 
tonsil,  319 
triangle,  04 

dissection,  64 
vein,    9-.',    IIJ.    35.    50,  51, 
70,  177.   645 
relations,  11 2 
Lingualis  m.,  220 

inferior,  220,  221 
superior,  220,  221 
Lingula,  513 

of  cerebellum,  561 
Lip,  lymphatics,  210 
Lips,  210 

lymphatic  vessels,  223 
Lobe    of    cerebellum,    biveutral, 
560 
central,  ,561 
digastric,  562 
posterior     inferior,   562, 
560 
superior,  561,   560 
quadrate,  .5(!1,  560 
slender,   560 
of  cerebrum,  central,  470 
frontal,  475,  4.-'l,  471 
inner  surface,  485 
landmarks,  508 
orbital     surface, 
482 
lind)ic,  landmarks,  499 
occipital,   176,  490,   458 
i  n  f  e  r  i  o  r   surface, 

494 
landmarks,  509 
parietal,  476,  485 

landmarks,  509 
quadrate,  516 
temporal,  4^1,  491,  471 
inferior    surface, 

494 
latid  marks,  509 
teniporo-sphenoid,     456. 
4^1.     491,     458, 
565.      Vide  Robe 
of     Brain,     Tem- 
poral, 
landmarks,  ,509 


Lobes  of  brain,  frontal,  4,'>() 

temporal,      I5().  ]'i(lr 

Lobe,     Temporo-.^ijlie- 
noid. 
of  cerebellum,  .5,")8,  561,  562 
of  cerebrum,  469 
of  i)arotid  gland,  656 
optic,  5;i-< 
Lobule  of  cerehellum,    erescenlic, 
anterior,  560 
l)osterior,  560 
of  cerebrum.      ]"nli  ('<inv(du- 

tions. 
of  car,  399,  6(;(l,  398,  661 
of  nose,  2S1 
of  testicle,  64M 
Lobvilus centralis,  561,  560 

gracilis,  5()2 
Locus  ca.'rulcus,  5  17 

jiiger,  553,  488,  497 
Long  buccal  n.,  6~<>^ 
Longitudinal  lissure.  459,  480 
line,  507,  506 
of  brain,  467 
median  sulcus,  542 
sinus,  inferior,  724,  714 

superior,  719,  709.714, 
715 
course,  592 
line,  719 
wounds,  719 
LongTis  colli  m.,  155,  39,  152 
action,  156 
in.sertion,  1.55 
nerve  stipply,  156 
origin,  155 
relations,  155 
Ludwig's  angina,  64 
Lung,  apex,  18 
Lripus  vtilgaris,  293 
Luscbka,  ]iharyngeal  tonsil,  232 
Lj'inpbatie  duct,  KiO 

gland,    auricular,    posterior, 

157 
glands,  auricular,  702 
buccal,  702 
cervical,  deep,  157 

superlicial,  157 
infra<-Ia\ic'ular,  157 
lingual,  703 
uiastoid,  702 
maxillary,  703 
occipital!  702,  157 
of  carotid  sheath,  73 
of  head,  702 
of  neck,  159,  157 
parotid,  6.57,  702,  157 
posterior  i)liaryngeal,  7015 
submaxillary,     63,    702, 

157 
sulioceipital,  702 
Lymphatics,  auricular,  jiostcrior, 
615 
frontal,  615 
occipital,  612 
of  brain,  445 
of  external  aialitory  meatus, 

407 
of  eyeball,  392 
of  eyelids,  6.55 
of  face,  703 
of  internal  ear,  438 
of  larviix,  265 


54 


INDEX. 


Lymphatics  of  lip,  210,  223 
of  inieklle  ear,  425 
of  mouth,  223 
of  nasal  foss;e.  307 
of  neck,  157 
of  nose,  2^t() 
of  orbit,  351 
of  jiharynx,  238 
of  pinna,  403,  665 
of  ptervgo-niaxillary  region, 

6«7  ' 
of  scalp,  613,  703 
of  tongue,  223 
of  tonsils,  225 
posterior  auricular,  615 
temporal,  615 
Lymph  passage  of  eve,   anterior, 
392 
posterior,  392 
spaces,  intervaginal,  385 
of  cornea,  392 
of  iris,  392 
perichoroid.  393 
supra- \aginal,  324,  395 
Lyre,  522,  533 

M. 

MacEven,   supra-meatal  triangle, 

415 
Macroglossia,  223 
Macula  lutea,  380,  381 
Magendie,  foramen,  441,  544 
Malar  branch   of  fncial  n.,    609, 
613,  620 
of  lacrvnial  a..    336 
of  orldtal  n.,  351,  694 
of  tcniporo-facial  n.,  (ifi9 
of  teniporo-iualar  n.,  676 
Malleolus,  ligament,   suspensory, 

422 
Malleus,  423,  405,  409,  413 
caries,  424 
handle.   418,  422 
head,  422 

ligament,  anterior,  424 
external,  424,  409 
internal,  424 
superior,  423,  434 
suspensory,     434,     409, 
413 
manubrium,  423 
processus  brevis,  433 

gracilis,  423 
short  process,   418 
Mammary  a.,   inti-rnal,    146,  78, 
79,  129,  133 
gland,  carcinoma,  pain,  45 
Manubrium  of  malleus,  423 
jMargiual  convolutions,  485,  488, 

497,  516 
Masseter  m.,  6.50.  621,  627 
action,  (iiio 
blood  supply,  660 
insertion,  (i59 
nerve  suj)ply,  660 
origin,  650 
relations,  (i.59 
Masseteric  a.,    (H4,    620,    678, 
682 
nerve,  687,  621.  678 
portion    of    Stcnson's    duct, 
659 


Mastoid  abscess,  420 
antrum,  412,  413 

trephining,  415 
artery,  95,  96 

branch  of  auricularis  maguus 
nerve,  38 
of  small  occipital  nerve, 
51 
cells,  412,  416,  413 
disease,  pus,  423 
lymphatic  glands,  702 
nerve,  30.  34 
process,  5;il 

operations,  723 
vein,  37 
Maxilla,    inferior    condyle,    exci- 
sion. .584 
excision,  583 
fracture,  586,  581 
superior,  excision,  579 

line    of     incision, 
572 
fracture,  586 
Maxillary  a.,  internal.  679,  680, 
133.    620,    621, 
678,    682,    686. 
695 
branches,  683.  682 
divisions,  683 
division  of  internal  maxillarv 

a.,  683 
lymphatic  glands,    internal, 
■  703 

nerve,  inferior.  687.  730,  326, 
339,   686,    695, 
715 
branches,  687 
neurectomy    of    in- 
tracranial, 
730 
structures      in- 
\olved,  730 
resection,  199 
superior,   693,   698,   7:;0, 
326,    339,    678, 
686,  715 
brandies,  694 
course,  693 
infra  iirl)ital  branch, 

609 
neurectomy   of,    in- 
tracranial, 
730 
structures      in- 
volved, 730 
resection,  199 
sinus,  313.      Mile  Antrum  of 

Highmoie. 
vein,  anterior,   6'^7,  35.  645 
internal,    6«7,    35,     50, 
70,  645 
Measurements  of  orbit,  317 
Meatus,  auditorv,   external,   403, 
405,  409 
blood  suiiply,  404 
lymphatics.  407 
nerve  sujiply,  407 
occlusion,  404 
relations,  404 
sinus,  403 
M'ins,    107 
inferior,   212 
of  no.se,  296 


Meatus  of  nose,  fourth,  299 

inferior,  299,  296,  298. 

350 
middle,  399,   212,  296, 
298,  350 
atrium,  299 
superior,  299,  212,296, 
298 
Meckel's    ganglion,     097,     303, 
686,  690 
branches,  697 
removal,  699 

structures  involved, 
699 
space,  730 
Media,  refracting,  of  eye,  361 
Median  fissure,  longitudinal,  544 
posterior,  542 
nerve,  149 

sulcus,  longitudinal,  542 
Medulla  oblongata.  461,  553,  516, 
539,  552 
fissure,     antero- lateral, 
554 
anterior   median, 

55.3,  552 
posterior  median, 
553 
function,  558 
funiculus  dentatus,  536 

gracilis,  536 
position,  456 
pyramid,  anterior,  458 
P3'ramids,  554 

decussation,      553, 
,554.  552 
tract,  lateral,  .554,   536, 
552,  556 
pyramidal,  552 
Medullary  velum,  posterior,  562 
superior,  543,  516,  536, 
542,       560.         Vide 
Valve  of  Vieussens. 
Meibomian  glands.  593,  6,52,  346, 
355,  632,  653 
ducts,  648.  353 
orifice,  653 
Melanotic  s;n'e(ima  of  choroid,  379 
Membrana  basilaris,  432 
flaccida,  419.  409 
nictitans,  321 

rudimentarj',  651 
tensa,  419 

tympani,     416,    405,    409, 
413 
artilicial,  420 
blood  supply,  420 
external  view,  418 
folds.  419 
inner  vail.  420 
internal  view,  422 
mucous  membrane,  430 
nerve  sup])ly,  420 
paracentesis,  419 
perforation,  419 
promontory,  430 
jivraniid,  420 
rupture,  4I!I 
.seciuidaria,  420,  4,32 
Membrane,  crico  tinroid,  24,  255, 
123,  251.  254 
hyaloid,  385 
b'vpo-glossal,  216,  230,  270 


IX  HEX. 


755 


Membrane,  intci'sutiiial,  (!17 
mucmis,  of  larynx.  'Jdli 

of   iiieniliiana    tviiipani. 

of  llloutll,  "Jl.'i 

of  iiasiil  fo>s:v,  :il)0 

of    luise,    iieive   supply, 

:!()-J 
of  pharynx,  232 
of  liownian.  303 
of  luain.  704 
of  Deseeniet.  363 
of  Reissner,   i'.K 
pituitary,  300 

nerve  supply,  303 
pupillary,  3(i7 
Sehneideriaii,  300 

nerve  supply.  30'> 
Sluapnell's,  41!)",  418 
synovial,    of   teiuporo-nuixil- 

larv  articulatiiiM,  ."i74 
thvro-livoi,!.  ■,>,-..-,,  123,  212, 
251.  254.  263 
Meniluanes  of  brain,  43>^ 
Menihranoiis  cuclili'a.  437 
labyrinth.  431.  432 
'  diaKrani,  439 
semieireular  canals,  437 
M^'ni^re's  disease,   437 
Meningeal  a.,  anterior,  734 

middle.    .^i92.    (i-^:!.    733. 
303.    682.    688, 
690,    695,    709, 
714.  715 
brauehes,  733,  734 
wounds,  734 
posterior,    95,  449,   735, 

444 
small.    fi'<3.     735,     682. 
686.  695 
branch   of  anterior   ethmoid 
artery,  337 
of  a.sceuding  pharyngeal 

artery,  97 
of  gl  osso-p  h  a  r  y  n  g  e  a  1 

nerve,  llfi 
of  pueuuiogastric  nerve, 
81 
vein,  735 
Meningitis,  423 
Meningocele.  591 

sincipital.  28() 
Mental  a..   (17<i.   i'<:'.   620,  682. 
695 
anastomosis,  (i'li 
branch     of     mvlo-bvoid    n., 

(i91.  695 
foraTueii.  .")9.'> 

nerve,  (i7(i,  609.  620.  686 
Mever,  .spheno-ethnioid  recess  of, 

299 
Middle  ear,  399.  407 

blood  supi)ly,  425 
disease.  420 
<lissiction.  407 
lymphatics,  425 
pyr.aniid.  412 
veins,  42.") 
.Mobilitv  of  eyeball,  3.57 

of  sirali),'l>l(i 
Modiolus,  432.  434.  436 
Molar  glands.  213 
Moll,  sweat  glan<i.  353 


Monoplegia.  Iiracliial,  504 
crural.  ."lO  I 
facial,  aol 
.Monri>.   foramen,   ."ils,   537,  516, 

519.  528.  529 
Monticnlis  ccrebelli,  ,501 
clivus,  .'>()1 
cnlmen,  501 
Morgagni,  sinus  of,  2:!1.  229 
Motor  areas  of  brain,   1 19,  501 
centers  of  brain,  ."lOO 
oculi  n.,   341,  539.  715 
Mouth,  209,  213,  591 
angles,  210 
anterior  view,  239 
diaphragm  of,  107 
dissection,  209 
lymphatics,  223 
mucous  niemliranc,  215 
muscles.  031 
section,  212 
vestibule.  210.  212 
Movements  of  larynx,  24,  281 
JIucocele    of    antrum    of    High- 
more,  312 
Mucous  gland  of  Kustachian  tube, 
411 
of  laryn.N,  209 
of  nose,  302 
membrane  of  larynx,  209 
of    mend>rana   tympani, 

420 
of  mouth,  215 
of  nasd  fo.ssic,  300 
of  nose,  nerve  supi)ly,  302 
of  pharynx,  232 
of  urethra,  637 
Miiller,  paljiebral   muscle,   supe- 
rior, 353 
ring  niuscli'  uf,  373 
Multiliilus  spin;e  m..  39 
Muscie  volitantes,  385 
Muscle,  anterior  dilator  narium, 
627 
antitragicus,  005.  401,  663 
arvteno  -  ejiiglotlidens,      261, 

258.  259.  263 
arvtenoideus,  256.  258,  259, 

'263 
attolens  aurem,  OO.'i,  627 
attrahens  aurem.  OO.'i.  627 
azvgos  uvuhc,  240.  242.  243 
bu'ecinator.    037.    229,   242, 

621.  627,  678.  686 
bnlbo-cavLM'nosus.  Oo  1 
ciliary.  30-^,  360,  365.  369, 
"  376.  394 

of   orbicularis   palpebra- 
rum, 0:!3 
complexns.  39.  50.  71,  78 
compre,s.sbr  narium.  627 
minor,  627 
nasi,  629 
constrictor,  of   pliarvnx,    in- 
ferior.    22-*.     71. 
79.      123.      177, 
229.  236.  251 
middii'.      ■:■}■'.       50. 
71.79,  105,  229 
supt-rior.     22"^.     71, 
79.  229 
corrugator     snpercilii,     634, 
346.  632 


Muscle,   crico-arytenoideus  later- 
alis, 201.  259 
posticus,  2.">0,  258.  259 
cricothyroid.  2.'i.'>.  123,  251 

jiosteridr.  263 
dcpre.s.sor  al;e  nasi.  030 
angnli  oris.  627 
labii  infrrioris.  030.  627 
digastric.    9s.    71.    78,    79. 
105,  117 
anterior  billy.  50 
posterior  lielly.  50 
dilator  naris,  029 

narium.  antirioi,  627 
jioslerior.  627 
external  jiterygdid.  (I"9,  678 
genio-livo-gldssns,    111.    220, 

78,  79,    105,   109.   212, 
296 

ginio-hvoid.  107,  78.  79, 
105.  109,  212.  296 

helicis  major,  0(i.").  401.  663 
minor.  005,  401,  663 

Horner's,  (i33.  Vide  Tensor 
Tarsi  Muscle. 

hvo-glossns.  10-J.  220.  71,78, 

79,  105,  109,  177 
inferior   obIi(|nr.    347,    320, 

339.  632 
reclns.  632 
internal  jili  rv^Luid.  Il-O.  303, 

678.  686.  690 
la.xator  tymjiani.  424 
levator  angnli  oris.  0,30,  627 
scapnhe.  39.  50,  71, 
152 
glandiihe  ilivroidea;,  122, 

124,  251 
labii  inl'crioris,  030 

snpeiioris,  035,  627 
aUcque      nasi, 
029,  627 
menti,  627 
palati,  245.  242,  243 
palpcbric  sniii-iinris.  320, 
32^.   0.'..").    326.    330, 
334,  353.  355.  653 
paliiebial.  339 
lingual  is.  220 

inferior,  220.  221 
superior.  220.  221 
longus  colli.  l.")5.  39.  152 
niasseter.  0.")9.  621,  627 
multilidus  s]>iiue,  39 
mvlo-hvoid,     107.      50,     71, 
78.   79.    107.    109.    177, 
296 
oblique,  infnior.    :117.    326, 
330.  334,  339    346. 
632 
superior.  331.  326.330. 
334 
jiulley,  331.  334 
obliquus    anris,     6()5,     401, 
663 
capitis  inferioris.   152 
superioris.  152 
occipitalis,    015.    79.        Vide 

Oecipi  to-frontal  is  Muscle. 
oceii)ito-fron talis.  015 
omohyoid,  119.  71.  117 
anterior  belly.  119.  50 
posterior  belly,  120.  50 


756 


INDEX. 


Muscle,  orbicularis  oris,  634,  627 
palpi'l)raruMi,   (i30,   321, 
353,  627 
palatn-gl.issus,  :.':J0,  240,  105, 

109,  242,  243 
palatd-pharvugc'us,  245,  242, 

243 
palpebral,    superi(.)r,   of  Mul- 

ler,  353 
platvsma    nivoidt-s,    31,    30, 

177,  621,  627 
posterior dilatornarium,  627 
pterygoid,  external,  679,  678 
■internal,  OSO,  303,  678, 
686,  690 
P3-r.aniidalis  nasi,  626,  627 
quadratus  nienti.      \'i(h  De- 
pressor    Labii     Inferioris 
Muscle, 
rectus  capitis  anticus  major, 
156,  78,  79, 
152 
minor,  156, 152 
lateralis,  156,  152 
external,  342,  321,  326, 

330,  334,  339 
inferior,  347,  339,  346, 

496 
internal,  342,  326,  330, 

334,  339 
superior,  331,  320,  326, 
330,  334,  339,  346, 
632 
retrahens  aurem,  605,  627 
ring,  of  Miiller,  373 
risorius,  31,  634,  627 
salpingo  -  pharyngeus,      245, 

243 
Sautorini's.        Vide   Risorius 

Muscle, 
scalenus    antieus,    1.^3.    39, 
71,  78,  79,  129.  152 
medius,  154,39,  50,71, 

129,  152 
posticus,   154,  39,  129, 
152 
semispinalis  colli,  39 
serratus  magnus,  50,  71 
sphincter    oculi.        IVrfe   Or- 
bicularis Palpebrarum 
Muscle. 
oris.        V'kJi'  Orl>icularis 
Oris  Muscle, 
splenius,  39,  78,  79 

capitis,  50,  71,  152 
stapedius,  425,  422 
sterno-cleido-mastoid,  17,  48. 
Vitle  Muscle,    Steruo-Mas- 
stoid. 
stenio-livoid,     120,    39,    50, 

71,  78,  117 
sterno-niasldiil,    17,    4^^    39, 
41,  50,  71,  78,  117,  177 
stenio-tlivroid,    121,   39,   50, 

71,  78,  117 
stvlo-glo.^sus,    111,    220,    79, 

105.  109 
stvlo-livoid,   '.)■<.    50,  51,  71, 

105,  177 
stvlii-|il],'ii  vngcus,     115,     79, 

105,  229 
siipcrlicial  crrvical,   31 
superior  rectus,  632 


Muscle,  temporal,  625,  321,  621, 
678,  686 

tensor  palati.  245,  303,  690 
tarsi,     63:!,     321,    346, 

355,  632,  653 
tympani,  425,  405,  422 
thyro-arytenoidi'us,  2(il,  259 
ihyro-epiglottideus,  261 
thyro-hyoid,     121,    50,     71, 

87 
trachelo-niastoid.  152 
tragicus,  66.5,  401,  663 
transversalis  colli,  39 
trausversus  auris,   665,   401, 
663 
deep,  613 
trapezius,    39,   41,    50,    71, 

78,  79 
zygomaticus  major,  636,  627 
minor,  637,  627 
Muscles,  constrictor,  of  pharj'ux, 
228,  231,  229 
intrinsic,  of  pinna,  400,  401, 

663 
of  auricle,  intrinsic,  400 
of  ear,  605,  665 
of  esophagus,  229 
of  eyebrows,  630 
of  eyelids,  630 
of  face,  626,  613,  627 
of  larynx,  258,  259 
extrinsic,  262 
intrinsic,  262 
of  mouth,  634 
of  neck,  dissection,  48 
of  nose,  626 

of  orbit,  328,  326.  330 
of  palate,  paralysis,  247 
of  pharynx,  227 

paralysis,  247 
of  scalp,  613,  627 
of  soft  palate,  242,  243 
of  tongue,  219 

dissection,  108 
extrinsic,  219,  109 
intrinsic,  220 
of  tympanum,  425 
prevertebrial,  1,55,  152 
recti,    common    tendon,    in- 
ferior, 347 
superior,  347 
Muscular  branch  of  facial  a.,  643 
of  ophthalmic  artery,  337 
sense,  area  (jf,  500 
Musculo-cutaneous  n.,  149 
Musculo-spiral  n.,  149 
Mylo-hvoiil    a.,    104,    0.83,     678, 
682,  686,  695 
muscle,  107,  50,  71,  78,  79, 
107,  109,  117,   177, 
296 
action,  107 
blood  supjily,  107 
insertion,  107 
nerve  supply,  107 
origin,  107 
relations,  107 
nerve,    101,    6i>l.    51,    678, 
686.  695 
branches.  695 
incisive  branch,   691 
mental  branch,  691 
Myopia,  363,  396 


Myopic  eye,  389 
Myxedema,  126 

N. 

Nares,  anterior,  284,  594 
posterior,  232,  236 
Nasal  a.,  337 

anastomosis,  337 
lateral,  613,  682,  695 
bones,  28G 

fracture,  2^6,  586 
braudi   of  anterior  ethmoid 
a..  337 
of  infra-orbital   n.,    675, 

097,  620 
of  Meckel's  ganglion,  698 
catarrh,  301 
cavities,  294 

blood  supply,  307 
divisions.  300 
\eins,  307 
columna,  594 
douche,  308 
duct,  3.52,  594,  314 

orifice,  299,  298 
fossse,  294 

anterior  view,  306 
divisions,  300 
lymphatics,  307 
mucous  membrane,  300 
olfactory  portion,  300 
posterior  view,  309 
respiratory  portion,  300 
nerve,    302.    :i:;2.    075.     697, 
303,  326.  339,  343, 
609,  620,  690,  695 
branches,  335 
external  branch,  676 
inferior,  303 
naso-lal)ial  branch,  629 
of     Meckel's     ganglion, 

698 
superior,  698.  303,  690 
nerves,  inferior,  690 
polvpi,  301 

septum,  294,  236,  291,  306, 
714 
deviation,  294 
perforation,  294 
Naso-labial  branch  of  na.sal  n.,  629 
Naso-iialatine  a.,  684,  690 

branch  of  Meckel's  ganglion, 

698 
nerve,  309,  303 
Na.so-pharvnx,  227,  212,  296 
Nates,  538",  542,  556.  560 

brachia.  543 
Near-sightedness,  363 
Nebula,  364 
Neck,  ab-scess  of,  31,  47 
arteries,  ligation,  160 
articulations,  ,573,  579 
back  of,  surface  anatomy,  24 
bursa\  156 
carbuncle.  26 
develo]iment.  25 
dissection.  17.  26 
fascia,  deep,  34 

su))erlicial,  26 
incision  for  dissection,  623 
injuries,  31 
length,  17 


« 


i.\Di:.\'. 


757 


Neck,  Ivmiiliiitic  ulamls,  \M),  157 
vrssi'ls.  157 
iiiiisfU's,  (lissfftioii,  4S 
iieiv.s,  70,  71 

operations  iipun,  I!h; 
skin,  17,  'Jli 
surface  niai'klii;is.  21 
transverse  seetioii,  39 
triangles,  ,')-! 

anterior.  H 
tlia^jrani,  55 
dissection,  51 
posterior,  18 
veins,  35,  645 
vessels,  70,  71 
Necrosis  of  tnrliinated  liones,   :?00 
Nerve,  al)ilucent.    Hi,'),  1:!^,  539. 
I7(/c  Nerve,  Si.xtli  Cranial. 
ansii  liypojilossi,  71 
anterior  auricnlar,  IWS 

superior      dental,      (597, 

695 
temporal,  678,  686 
Arnold's,  81 

auditory,  i:W,  -K!."),  7il),  539. 
['/(/(■  Nerve,  Kiglith  Cranial. 
aurieiUar,  ><1 

anterior,  G*^*^ 

great,  30,  609 

of    auricularis   magnus, 

3S 
posterior,    it7,    61'-J,   iV<(i, 
51,    70,    71,  78,  79, 
203 
auricularis  uiagnus,    32,    38, 
34,  51 
branches,  3,-^ 
relation,  206 
auriculo-teni]>oral,    (il'i.  (W8, 
193,  303,  609,  613, 
620,  678,  686,  690, 
695 
divisions,  688 
operation  to  expose,  20.5, 
193 
buccal,  ii(ilt,  609,  613,  620, 
678,  695 
long,  IW-^,  686 
cardi.ae,  78,  79 

cervical,   pneumogastric, 
83 
sympathetic,      infe- 
rior, 85 
superior,  84 
middle.  So 
carotid,  of  glossopharyngeal, 

116 
cervical,  eighth,  149 

anterior  division, 79 
fifth,  149 

anterior      division, 
39,  71,  78 
fourth,  149 

anterior       division, 
71,  78 
second,  anterior  division, 

71,  78 
seventh.  149 

anterior       division, 
71,  78 
sixth,  149 

anterior        divi.sion, 
39,  71,  78 


Nerve,    cervical,    snperlirial,     I,"), 
34,  51 
relations,  o{k; 
third,    anterior  division, 
71,   78 
eervieo-t'aeial.  (ili!) 
hrariehes.  (111!) 
chorda    tvnipani,      126,    691, 
422,    678,    686, 
695 
in  otitis  media,  426 
ciliary,  376 

long,  33,j,  376 

posterior,  326,  377 
sliort,  339,  376 
posterior,  377 
circnnille.x,  149 
cochlear,   138,  .Kji; 
commnniiuintes      liypoglossi, 
(i6,  71 
noni,  6(i 
cranial,  715,^0/ 

eighth.    l(ir>,    458,  542, 
556 
origin,   552 
eleventh,   ,')7.    16(i.  458, 
542,  556 
origin.  552 
fifth,     4li,'.,     326,    339, 
458,  542,  556 
ophtlialiniedix  ision, 

326 
origin,  552 
fourth,    :!.'7.    -U\-2.    326, 
339     343,    458, 
542.    556,    560. 
V  i  d  e       Pat  hetic 
Nerve, 
origin.  552 
recurrent       branch, 
326 
ninth,    466.    458,    542, 
556 
origin,   552 
second,  462.    (VrfeNerve, 

Optic, 
seventh,  465 

origin.  552 
sixth.     341.    46.">,     326, 

339.  458 
tc-nth.     7li.      166,      458, 
542,  556 
origin,  552 
third,     3n,     462,     326, 
458.   17*  Nerve, 
Ocnlo-motor. 
origin.  552 
twelftli,  104.  467,  458 
origin,  552 
cutaneou.s,  internal,  149 
lesser  internal,  149 
deej)  temporal,  687 
dental, anterior  superior,  697, 
695 
inferior,  691,  678,  686, 
695 
line,  20,  67 
operation  to  exjjose, 

182 
resection,  200 
middle  superior,  694, 695 
iwsterior  superior,    (i94, 
695,  678,  686 


Nerve,  desci'ndens  hvpoglossi,  73, 
41,  51,  71,  78 
noni,  73 
digastric,  669 
eighth  cervical,  149 

anieriordivisioo,  79 
cranial,     K;,"..   729,    458, 
542,  715 
eleventlicrani.-il,  07,  466,  729, 

458.  542    715 
cMernal  palatine,  611(1 

resi)iiatory,  of  Hell,  153 

SU|ierticial  lietro,sal,  7,'!3 

facial,  46,">,  666,  728,  51,  71, 

78,    79,    203,    539, 

620,621.   („/,  Nerve, 

J^eventh  Cranial. 

briinches.  666 

buccal  l.iancli,  669,609, 

613,  620 
course,  66() 
digastric  branch,  669 
division  of,  facial,  666 
intra-cranial.  666 
temporal.  66(! 
infra-ma.\illarv    Ijranch, 

670.  34,  620 
infia  (irbilal  )iiaiH4i,  669, 

609,  613,  620 
line,  20,  27.  67 
malar  branch,  669,  609, 

613,  620 
of   auriculaiis    magnus, 

38 
oiieration  to  expose,  675, 

203 
paralysis,  (i70 
stretching,  205 
stylo-hyoid  Ijranch,  669 
supi'a-maxiniu'\'  br.-tnch, 
6-;0,  609,  613,  620 
temiionil     luanch,     612, 
609,  613,  620 
fifth  cervical,  149 

anterior  division,  78 
cranial,     465,    675,    728, 
326,    339,    458, 
542,  695,  715 
branches,  67.5 
ophtlialmie    d  i  v  i  - 
sion,   326 
first  cervical,  539 

cranial,  461,   727.      Vide 

Nerve,  Olfactory, 
thoracic,    anterior    divi- 
sion, 79 
fourth  cervical,  149 

anterior    d  i  v  i- 
sion.  78 
cranial,    327,     462.    7-J,'', 
326.    339.    343, 
458,    542,    715, 
l'i(/r    Nei'\e,     Pa- 
thetic, 
recmrent  bra  n  e  h, 
326 
frontal,  327.  326,  339,  343 
glo.s.so-pharvngcal.    115.    MM, 
729.' 79.    539.      (7</c 
Nerve,  Ninth  Cranial, 
branches,  116 
relations,  116 
tympanic  branch,  426 


768 


INDEX. 


Nerve,  gustatory,  112,  688 

hypoglossal,  104,  112,  467. 
5.54,  7Jil,  51.  71,  78, 
79,  177,  539.  Vide 
Nerve,  Twelfth  Cra- 
nial, 
paralysis,  104 
hypo^lossi  desceiidens,  71 

ooiuimiiiifantes,  71 
iiicisive     braiifh      of     mylo- 
hyoid, 691,  695 
ilifeVioi-    dental,     6!)1,     595, 
678,  686 
iiKi.\illai'v.      6-<T,      730, 
686,  695,  715 
liraaches,  687 
divisions,  687 
iienrectomy,     intra- 
cranial, 730 
nasal,  690 
infra-maxillary     branch     of 
eervico-facial,         670, 
620 
of  cervico  facial,  45 
of  facial,  34 
infra-oihital,  67."i.  695 

branch  of  superior  max- 
illary, 675,   697,   609, 
620,  695 
brandies,  075,  697,  609, 
620,  695 
labial,  675,  620 
nasal,  675,  620 
palpeliral,  675,  620 
operation  to  expose,   699 
structures      in- 
volved, 699 
resection,  19!) 
infratnirhlear,  3;i5,326,609, 

613,  620 
intercostal,  first,  149 
Intra-cranial,  72  r 

course,  727 
Jacobsou's,  116 
labial,  675,  697,  620.  695 
lacrvnial,  ii23.  327,  675,  326, 

339,  343 
laryngeal,  ext-rnal,  262,  51, 
71.  78,  79,  177 
inferior,  82 

internal,    262,    51,    71, 
78,     79,     123,    177, 
251,  263 
recurrent.  127,  262,  71, 

78,  263 
superior,  62,  81,  832 
irritation,  82 
])aralysis,  82 
lingual,    112,  ^W-^,  78,  202. 
678,  686,  695 
branches,  6^8 
irritation,  223 
of  gIosso-))harvngeal,  119 
ojn-ration  to  c.\posc,  202 
relations,  112 
resection,  205 
long  buccjil,  688 
malar  branch   of  facial,    669, 
(i76,     609,     613, 
620 
of  orbital,  351,  694 
masseteric,  6-^7.  621.  678 
ma.st<)id,  30,  34 


Nerve,  mastoid,  branch  of  auricu- 

larismagnusn.,38 

of  small  occipital,  51 

maxillary,  inferior,  687,  730, 

■     326    339,    686, 

695    715 
}>ranclies,  687 
neurectomy,     intra- 
cranial, 730 
structures  in- 
volved, 730 
resection,  199 
superior,   693,    698,  730, 
326,    339,  678, 
636,  715 
branches,  694 
course,  693 
infra-orliital  branch, 

609 
neurectomy,     intra- 
cranial, 730 
structures  in- 
volved, 730 
resection,  199 
median,  149 

meningeal,  of  glosso-i)haryn- 

geal,  11 1; 

of  pneiimogastric.  si 

mental,  676,  609.  620,  686 

middle  superior  dental,  694, 

695 
motor  oculi,  341.   539,  715 
musculo-cutaneous,   149 
musculo-spiral,  149 
mylo-hvoid,     101,    691,     51, 
71,    117,    678.    686, 
695 
branches,   691,  695 
incisive  branch,  691 
mental  branch,  691 
nasal,    302.     332,     675.     697, 
303,  326,  339,  343. 
609,    620,    690,  695 
liranches,  33.> 
external  liranch.  676 
inferior,  303,   690 
nasolal)ial   liraneli,  629 
of  Meckel'sganglion.  698 
superior,  (;9s,  303,  690 
na.so-labial  branch  of   nasal, 

629 
nasopalatine,   302,  698,  303, 

690 
nintii  cranial,  466,  729,  458, 

542,  715 
occipital,  great,  609.  613 
small,  612,  609.  613 
occipitalis  major,  61'J,  79 
minor.  38,  612.  30,34.15 
mastoid  braneh.   34 
relations,  206 
oculo-motor,    3)4 1,    462,   727. 
l7(/c  Nerve,  Third  Cranial, 
olfactory,  302,  461,  727,  303, 
690,'     Viilf    Nerve,     Finst 
Cranial, 
ophthalmic,  326,   339.   343, 

695.  715 
optic.  3  12.  162.  727.  320, 
326.  330.  334.  360, 
369  458,  516.  5r2, 
565,715.  \i<l,  Nerve, 
Second  Cranial. 


Nerve,  optic,  division,  316 
entrance,  362 
orbital,  351.  691,  339,    678, 
686,  695 
of     Meckel's     ganglion, 

697 
temporal     branch,     612, 
609.  613,  620 
palatine,  anteLiur,  697 

external.  m<.  303,  690 
great,  303.  690 
jjosterior,  (i9>^.  303.  690 
palpebral,    675,     (197,    620, 

695 
par.s  intermedia  of  Wrisbera, 

539 
pathetic,  327,  462,  728,  539, 
Vide   Nerve,    Fourth   Cra- 
nial, 
petrosal,  external  superficial, 
84 
small,  426 

superficial  external,  733 
large,  732 
small,  7:!2 
pharyngeal,  698,  303,  690 
of       glossoiiharyngeal, 

116 
ofpneumogastric,  81 
phrenic,   60,  65,  71,  78,  79, 

149 
plexus,   axillary,  148.      T'irfe 
Nerve    Plexus,      Bra- 
chial, 
brachial,     60,     14H,    51, 
71,  149,  208 
branches,  148 
formation,  148 
line,  20 
operation  to  expose, 

208 
stretching,  209 
cervical,  4S,  ()5,   44 
branches,  48 
descend  i  ngbrauches, 

51,  208 
superficial  branches, 
38 
pharyngeal,  8],  116,  231 
subtrapezial,  66 
tympanic,  426 
vertebial,  85 
pneumogastric,  76,  466,  729, 
39,  41,  78,  79,  164, 
539.        Vide    Nerve, 
Tenth  Cranial. 
liranches,  81 

cardiac      branches,     cer- 
vical, 83 
ganglia,  76 
relations,  76 
posterior  auricular,  612,  666 
sujierior      ileiital,      694, 

678,  686,  695 
temiioral.  678,  686 
pterygo-]ialatine.  ()98 
ramus      subcutaneus    mala;, 

694 
recxirrent    Inanch   of   fourth 
cranial,  326 
larvngcal,    82,    127,  78, 
79 
rhomboid,  149 


INDEX. 


759 


Nervi",   sccoiiil   ciMvical.    anterior 
tlivision,  78 
cranial,   l(i.">,   7'J7.      I'/i/i 
NiMVf,  Optir. 
seiisoiv,     of    |>anitiil    f;laiul, 

(i,">7  ■ 
septal,  of   Meckel's  ;;anf;li«>ii, 

(i!)s 
seventh  cervical.  149 

anterior       division, 
78 
cranial.   IH'i 
si.Mli  cervical.  149 

anterior      division, 
78 
cranial.   :!n.    Id.'),   326, 
339  343.  458 
splieno-palaliiie.  303 
spinal  accessory.  .")T,   liH!,  39. 
51,   71,   78,    79, 
539.   IV«/<  Nerve, 
I'.lexenth  Cranial, 
line.  20,  67 
operation  to  expose, 

182 
resi-ction.  .58,  205 
sterno-uiastoid,  71 
subscapular,  lower,  149 
niiadle,  149 
upjier,  149 
superlieial  cervical.  34 
siiperlicialis  colli.  4,") 
supraacroiiiial,  4,'i.  34 
snpra-clavieular.  \h,   34 
supra  maxillary     branch     of 

facial,  1)71).  620 
supra-orbital.  :!-.'7,  fill,  197, 
326,  339,  609,  613, 
620 
neurecloniv,  Gil 
operation  to  expose,  196, 
197 
supra  scapular,  1,53,  51,   71, 

149 
supra-sternal,  4."),  34 
supra-trix'hiear,      l!','7,      611, 
326,  339.  609,  613 
neurectomy.  Sll 
sympathetic.  78.  79 

cervical  portion.  83 
temporal,  anterior,  (il'.?,  686 
branch    of     facial,    ()12, 
()(>:i.    609,    613, 
620 
of  orbital,  l!.')!,   <)12, 
694,  609,  613 
posterior,  613.  678 
superficial,  6xH 
temjjoro  facial,  669 

branches.  669 
ti-ni]ic)ro-malar.  351.  694 
tenth.  7-J9.  715 

cranial.  466,  458,  542 
third,  727 

cervical,     anterior   divi- 
sion, 78 
cranial.    341.    462.  458. 
326.        Vide  Oculo- 
motor Nerve, 
thoracic,    external    anterior. 
149 
fii-st.  149 

anterior  division ,  7 9 


Xerve,  thoracic,  internal  anterior, 
149 
]iosirrior,    or   Ion;;.   1.53, 
51,  71,  149 
to    levator     angnli    scapulae 

muscle,  149 
to  lon;;us  colli  muscle,  149 
to  rhomboidei  ninsele,  148 
to  .scaleni  nuiscle,  149 
to  stylo  hyoid  muscle,  51 
to   snhclavius    mu.scle,    148, 

149 
tonsillar,    of    glosso-pharvn- 

fical,  119 
trifacial,  465,  675,  728,  339, 
539.       Vide      Nerve, 
Fiflli  Cranial, 
branches.  675 
trifieminiis,  465.    Vide  Nerve, 

Fifth  Cranial. 
trcKddear.  327.  462,  543.    Vide 

Nerve,  Fourth  Cranial, 
twelfth,  729.  715 

cranial,  467.  458 
tympanic,    of  ^losso  pharvu- 
'  «eal.  116,  426 
ulnar.  149 
vafius.  71).  729.      I7(/c  Nerve, 

Pnenmofaistric. 
vestibular,  438,  466 
Vidian,  302,  698,  303,  690, 
695 
Nerves,  ciliary,  379 

cranial,  oriijins,  552 

superficial,  origin,  458 
deep  temporal.  6^7 
of  face,    666,  609,  613,  620 
of  head,  oi)er/itions,  196 
of  Lancisi,  517 
of  larynx,  2(i2.  263 
of  neek,  70,  71 

operations.   196 
of  orbit.  327,  326,  339 

arranf;enieiit,  342 
of  pteryKo-maxilUiry  region, 

687 
of  scalp,  611.  609,  613 
of  thyroid  >;land,  126 
plexus  of.  basilar,  715 
infra-orbital,  669,  675 
Nervi  molles,  84.  644 
Nervus  vagus.  466 
Neuralgia,  trifacial.  698,  700 
Neurectomy,  intra-cranial,  of  in- 
ferior maxillary  n.,  730 
of  sui)erior  maxillary  n., 
730 
of  supra-orbital  n..  611 
of  sn])ra  trochlear  n..  611 
Xidus  hirnndinis.  562 
.Ninth  n..  729.  715 

oi-anial  n..     166,    458,    542, 
556 
origin.  552 
Nodule  of  cerebellum,  562,    560 
Nose,  2^<4,  594 

air-chambei-s,  accessory,  314 

orifices,  298 
ala;,  2'<4 
b.i.se.  2.-^  1 

bUediiig  from.  301 
blo(Ml  su|)ply,  285 
bridge,  284 


298, 

298 

298 

sup- 


Nose,  cartilages,  2H6 

accessory,  293 
at  ba.si-,"290 
lateral,  287 

inferior.  286 
sesiimoid.  293 
dis.section,  284 
divisions,  284 
epithelioma,  2>'5 
hemorrh,if;e  from,  301 
lobule,  2^4 
lymphatics,  2X6 
nieirtns,  296 
fourth.  299 
inferior,  299,  296, 

350 
middli-,  2:19,  296, 
350 
atrium  of.  299 
su|)erior.  299.  296, 
mucous  ghuwls.  302 
membrane,     nerve 
ply,  302 
nerve  su))ply,  285 
rodent  ulcer,  285 
section,  212 
skin,  285 
veins,  2K5 
vestibule,  285,  303 
wings,  284 
Nose-bleed,  643 
Notch  of  Hivini,  416 
preoccipital,  476 
supra-orbital.  316 
Nuclei  of  brain.  536 
of  jions  Varolii,  .5,50 
of   tegmentum   of  cms 
bri,  5,53 
Nucleirs,  caudate,  525,  517, 
542,  546,  556, 
569 
head,  536,  564 
cuneate,  557 
Deiters',  465 
gracile,  557 
lenticular.     ,525,     54-*, 

564,  565,  569 
of  lens,  391 
olivary,  superior,  550 
red.  553 
tegmental.  553 
Nuhu,  gland,  219 


Oblique  m.,    inferior.    347    320. 
326,    330,   334, 
339,  346,  362 
action,  317  / 

insertion,  347        / 
nerve  sui)i)ly,  348 
origin,  347 
superior,  331.326,330, 
334 
action,  331 
insertion,  331 
nerve  sup])ly,  331 
origin,  331 
pnllev,    331.     334, 
632 
Obliquus  aurisni..  665,  401,  636 
capitis  inferjoris  ni.,  152 
superioris  m.,  152 


529, 
565, 


546, 


760 


INDEX. 


Occipital   a..    !i:!,    50,    70,  133, 
603,  608,  613,   640 

anastomosis,  606 
brandies,  94 
irregularities,  1 95 
ligation,  94,  195 
operation  to  expose,  183, 

192 
relations,  93 
convohrtioii,     inferior,      491, 
474,  477,  480 
middle,  491,   474,  477, 

480 
superior,  491,  474,  477. 
480 
diploic  v.,  707,  705 
fissure,  inferior,  49(1 

middle,  490,  477,  480 
posterior,  line.  506 
superior.  490.  477,  480 
trausvcisp,     490.      477, 
480,  572 
foranien,  superior,  718 
lobe,  476,  490.  458 

inferior  surface,  494 
landmarks.  5(t9 
lymphatic  gland,  157 

glands,'  702 
lymphatics.  612 
nerve,  great.   612,   79,    609, 
613 
small,  612.  30,   34,  51, 
609    613 
mastoitl  branch,   34 
protuberance,    external,    25, 

,"591 
sinus,  724.  715 
suture,  traMs\erse,  573 
triangle,  54,  55 
abscess,  59 
content.s.  57 
dissection,  57 
vein,  95,  35,  645 
relations.  95 
Occipitalis  major  n..  612 
minor  u.,  :is,  612 

rehitions,  206 
muscle,  615.  79.      Vide  Occi- 
pito-fron talis  Muscle. 
Oecipito-angular  region,  503 
Occipito  -  frontalis      aponeurosis, 
61.5,  599,  627 
muscle.  615 
action,  615 
aponeurosis,    615,    599, 

627 
blood  supjily,  615 
insertion.  i'A'y 
nerve  supply,  615 
origin,  (il5 
relations.  f>15 
Occipito  •  tem))oral    convolution, 

external,  495 
Occlusion  of  Eustachian  tube,  411 
of  external  auditory   meatus, 
404 
OcHlo-motor   n.,    341,    462,    727. 

Mtlc  TInrd  ('raiiial  Xcrve. 
Olfactory  l)nlh,   l,5(i.  458,  483 
fissure.    1.56.  4S2,  488,  497 
nerve.   302,    461,    727,    303. 
690.      Villi-   First  Cranial 
Nerve. 


Olfactory  portion  of  nasal  fossx, 
300 
sulcus,  456 

tract,    4.56,    462,   303,  458, 
539,  690 
Olivary  body,  .554,  458,  539,  552 
corpus  dentatum,  554 
peduncle,  554 
nucleus,  superior,  550 
Omo-hyoid  m.,  119,  71,  117 
action,  120 

belly,  anterior,  119,  50 
insertion,  120 
origin.  119 
posterior,  120,  50 
insertion.  120 
origin.  120 
nerve  supply,  120 
tendon,  39' 
Onyx,  364 

Operation,  enucleation  of  eyeball, 
396 
esopliagotoray,  226 
evisceration  of  eyeball,  396 
excision  of  condyle  of  inferior 
maxilla,  .584 
of  eyeball,  396 
of  inferior  maxilla,  583 
of  larynx,  281 
of  superior  maxilla,   579 
for  abscess,  cerebellar,  511 
extradural,  511 
temporo-sphenoid,  511 
for  cleft  palate.  215 
for  harelip,  210,  213,  644 

hemorrhage  in,  644 
for  headache,  512 
for    removal    of    Ga.sserian 
ganglion,  731 
structures      in- 
volved, 731 
of  parotid  gland,  658 
for  tongue-tie,  1 15,  215 
for  traumatic  ejiilepsy,  512 
for  trifacial  neuralgia.   699 
laryngotomy,  281,  279 
ligation    of    carotid    artery, 
common,  179 
internal,  195 
of    inferior   thyroid    ar- 
tery, 179 
of     innominate     artery, 

160.  165 
of  lingual  artery,  64 
of  occipital  artery,  195 
of  subclavian  artery,  132 
third  portion,169 
of  temporal    artery,  su- 
perficial, 195 
of  verteliral  artery,  143, 
175 
on  mastoid  process,  723 
resection  of  dental  nerve,  in- 
ferior, 200 
of    Gasserian    ganglion, 

199 
of  infra-orbital  nerve,  199 
of  lingual  nerve,  205 
of  maxillary   nerve,    in- 
ferior, 199 
superior,  199 
of    spinal   accessory 
nerve,  58,  205 


Operation,  rhinoplasty,  285 
Rouge's,  300 

stretching  brachial    nerve 
plexus,  209 
facial  nerve,  205 
thyroidectomy    126 
to   expose  auriculo-temporal 
nerve.  205,   193 
brachial    nerve    plexus, 

208 
carotid  artery,  common, 
182 
external,   183 
internal,  183 
facial  artery.  182,  183 

nerve.  203 
inferior     dental     nerve, 

182 
innominate  artery,  164 
lateral  sinus,  510 
lingual  artery.  183 

nerve,  202 
occijiital    artery,     183, 

192 
spinal   accessory    nerve, 

182 
subclavian  artery,   third 

portion,  167 
supra-orbital    arte  r  y, 
197 
nerve,  196 
temporal  artery,  193 
thyroid  artery,   inferior, 
174 
superior,  183 
vertebral  arteiy,  174 
to  tap  lateral  ventricles,   511 
tracheotomy,  122,  282,  279 
upon  nerves  of  head,  196 
of  neck,  196 
Operculum,  470,  471 
Ophthalmia,  purulent,  361 
Ophthalmic   a.,    335,   229,  334, 
444,  715 
branches,  335 
muscular  branches,  337 
division  of  fifth  cranial  nerve, 

326.  339 
ganglion,  338 
nerve,  343,  695,  715 
vein,  337,  343 

common,  338,  334 
inferior,  338,  334 
phlebitis,  338 
pulsation,  338 
superior.  338.  334 
Optic  chia.sm,  459,  334 

commissure,  459,   458,  483, 

494,  516,  539,  565 
disc,  380.  381 
lobes,  538 

nerve,    342,    462.    727.   320. 
326,  330,  334,  360, 
369,  458,  516,  552, 
565,      715.        Viilc 
Second  Cranial  Nerve, 
division,  316 
entrance  of,  362 
thalamus.     ,526,     ,538.     488, 
497,  519,  523,  536, 
542,  546,  552,  556, 
569 
pulvinar,  539 


INDEX. 


761 


Optic   tlKihuiuis,    tul)pivle,  nnte- 
rior,  :">:{--( 
|iiistcriiu'.  'ilN 
tract,    lii-i,   458.   539,  552, 
565.  569 
(li:iL;iaMi.  463 
Orii  si'iraui,  IWd 
Orl)ifularis  liliaiis,  :!7t 
oris  in.,  (i:!l,  627 

action,  (i3."i 
nerve  supply,  (i35 
ri'latidiis,  (;:>.) 
palpel)raniin   in..   (i:!ll,   321, 
353.  627 
actiDii,  U:!.'! 
insertion,  (>;!;{ 
nerve  .supply,  633 
orifjin,  (i30 
relations,  (530 
Orl)it,  3U! 

abscess,  3-23 
apex,  31  li 
arteries,  334 
l)a.se.  31(> 
dissection,  316 
enipliysenia.  323 
exenteration  of  contenta,  396 
floor,  316 
lymphatics.  .3.51 
measurements.  317 
muscles,  32-<,  326.   330 
nerves,  3-37,  326,  339 
arraufiement,  34'J 
perio.steum,  318,  320 
pulsjitiou,  338 
roof,  316 
veins,  334 
Orbital  a.,  608,  613,  640,   682 
branch  of  Meckel's  ganglion, 
697 
of  superior  maxillary  n., 
694 
convolution,     anterior, 
483.  488.  497 
inferior.  483 
internal,  4s,').  488. 
posterior.       4>.'>, 
488.  497 
fascia,  3J3,  320.  321 

lamina,  ,323 
fat,    323.    321,   326, 
632 
foreign  hofly,  323 
fis,sure,  4.56,  4*2.     r/rfeTrira- 

(liate  Fissure. 
nerve,  3.51.   339,  678,  686, 
695 
temporal     branch,     612, 
609,  613.  620 
sulcus.  4.")6 
vein,  35.  645 
Orbito-tarsal  ligament,  652,  320, 

321 
Organ  of  Corti,  437 
of  hearinir,  399 
Orifice,  buccal.  210 

of  antrum  of  Highmore.  298 
of  aque<luctus  cochlea,  430 

vestibuli,  430 
of  dnct  of  Meibomian  gland, 

653 
of  Eustachian  tube,  232,  298, 
422 
S— 49 


485, 


497 
483, 


330, 


Orilicc   of   lacrvmal    ducts,   355, 
653 
of  na.sal  duct,  291),  298 
Orilices  of  airchainlici-s  of  no.^e, 

298 
Oro-pharynx,  227,  212.  296 
Os  orbicnlare  of  incus,  424 
O.ssiclcs.  auditory,  423 
Ossilieation   of  cricoid   cartilage, 
274 
of  thyroid  cartilage,  247 
OthemaUnuata,  4l)ii.  iliKI 
Otic  ganglion,  (i9l,  303,  690 
Otitis  externa,  404 

media,    clumla     t  y  m  p  a  n  i 
nerve,  426 
during  dentition,  426 
liganuMits,  424 
pus,  423 
Otoliths,  437 
Oval   window,    420,    431.       Vide 

Fenestra  Ovalis. 
Ozena,  301 

P. 

Pacchionian    bodies,    445,     70S, 

709 
Pain  in  glaucoma,  362 
Palate,  cleft,  214 

operation,  215 
hard,  21  I.  212.  239,  296 
blood  su]>ply.  214 
nerve  .supi)lv,  215 
soft,    23"<,    212,'   236,   239, 
296 
cleft,  246 

muscles,  242.  243 
Palatine  aponeurosis.  2  Hi,  242 
a.si^'udinn.  92 
desi'ending,  30T,  105 
artery,  (is4,  682 
branch  of  a.scendiug  pharyn- 
geal artiMv.  97 
nerve,  anterior.  <I97.  ()98 
external.  303.  690 
great.  303.  690 
posterior.  69-^.  303.  690 
Palato-glo.ssus   muscle.   220,    246, 
105.  109.   242,   243 
.iction,  246 
insertion,  246 
origin,  246 
PalatD-pharvngeus  ni.,  245,  242, 
243 
action,  245 
insertion,   245 
origin,  24,5 
Palpebne,  (>IS 
Palpebral  art»»ry,  682 
inferior,  337 
superior,  337 
branch    of    infr.i-orliital    n., 
675,  697,  620.  695 
of  lacrymal  artery,  336 
of    supraorbital    artery, 
336 
commissures,  648 
fa.scia,  (!52 
fis.sure,  593.  649 
ligaments,  6,52 
muscle  of   Jliiller,  superior, 

353 
portion  of  conjunctiva,  651 


Palsy,  Bell's,  670 
Pannus,  364 

Papilhe.  circuiinallatc,  219,  109, 
218.  236.  250 
conjunctival,  353 
tilitorm,  219 
foliata,  219 

fungiform,   219,  218,  250 
lachrymaliie,  648 
Papillitis,  445 
Panu'cntesis   of   meinbrana   tym- 

pani,  419 
Paracentral      convolution,      489 
488,  497,  516 
fissure,   |M!I,  488.  497.  516 
Parallel  fissure,   192,  477 
Paralysis  of  facial  n.,  (i7l» 

of  bypo-glossal  nerve,  101 
of  larvngeal   nerve,  sui)erior, 

82 
of  larynx,  262 
of  muscles  of  i)Iiarynx,  247 

of  jialate,  247 
of  tongue,  220 
varieties,   .504 
Parietal  artery,  ascending,  447 
convolution,   ascending,   486, 
474.  477.  480.     Vide 
Post -cent  la  1    Con\'olu- 
tion. 
inferior,   l-ili,  480 
posterior,  474 
superior.    1S6,  477,  480 
eniinenee.s,  592 
fissure,  573,  572 
lobe,  476,  485 

laiKlmarks,   ,509 
Parieto-occii)itid  fissure,  475,  474, 
477,  480.  488.  494, 
497.  516 
Parieto-teniporal  a.,  447 
Parotid  ab.scess,  657 
incision,  6,58 
branch  of  post-ainicular  a.,  96 
fascia,  656 

gland,    63.    6.56.    157,    608. 
613.  627.  640 
contents.  (i57 
lobe  of,  c;irotid,  656 
glenoid,  656 
pterygoid,  656 
relations,  656 
removal,  658 
sensory  nerve  supply,  657 
wounds,  6.58 
lymphatic  glands,  657,  702 
Par  vagum.  4(i(i 
Pars  basilaris,'  4H2, 

ciliaris  retina;,  380 
intermedia  of  Wrisberg,  465, 

539 
iridiea  retina;,  380 
optical  retiuic.  .380 
orbitalis,  4«2 
triangularis,  482 
Patellar  fos.s,a,  385 
Pathetic  n.,  327,   462,  728,  539. 

Vide  Cranial  Xerve. 
Pectinate  ligament  of  iris,  364 
Peduncle  of  cerebellum,  inferior, 
567,  539.  542 
middle,   567,    539.  542, 
552 


762 


INDEX. 


Peduncle  of  cerebellum,  superior, 
543,  567,  536,  539,  542 
of  olivary  body,  554 
of   piueal   body,    516,   529, 
536,  542,  556 
Peduncles  of  cerebellum,  562 

of  cerebrum,  460,  550.      Vide 

Crura  Cerebri, 
of  corpus  callosum,  517 
Peduueular   fillers   of    cerebrum, 

548 
Perforated  space,   anterior,    459, 
458 
posterior,  400,  458 
Perforation    of    membrana    tym- 
pani,  419 
of  na.sal  septum,  294 
Perichoroid  lymph  sjiace,  392 
Pericrauium,  617,  599 
Periglottis,  270 
Perilymph,  431,  432 
Periorbita,  318 
Periosteal  branch  of  supraorbital 

a.,  336 
Periosteum  of  orbit,  318,  320 
Pes  accessorius,  531 
anserinus,  670 
hippocampi,  531,  523,  529 
Petit,  caual,  386,  360  ^ 

Petrosal    uerye,    external    super- 
ficial, 84 
small,  426 

superficial  exterual,  733 
large,  732 
small,  732 
sinus,  inferior,  726,  714,715 
superior,  726,  715 
throiulwsis,  423 
Petrous  ganglion,  116 
Pharyngeal      apoueurosis,      231, 
229.  243 
artery,    ascend  iiin.     97,    105, 
70,  78,    79,  229 
relations,  97 
branch  of  ascending  pharj'U- 
geal  a.,  97 
of  glosso-pharyngeal  n., 

116 
of  pneumogastric  n.,  81 
bursa,  232,  233 
diverticulum,  26 
nerve,  69S,  303,  690 

plexus,  81,  116,   231 
pouch,  2(> 

recess,  232,  233 
tonsil,  232,  233 

hypertrophy,  232 
of  I.uschka',  232 
vein,  descending,  97 
Pharyngitis,  232 

Pharyugo-e.sophageal  junction,  227 
Pharynx,  227,  242 
lilood  supply,  238 
coats,  'J'J7 

constrictor  m.  's,  228,  229 
inferior,  71 
middle,  71 
superior,  71 
di.ssection,  227 
divisions,  227 
fiMcigu  Inidies,  227 
interior,  236 
lympliatic-s,  238 


Pharynx,  mucous  membrane,  232 
muscles,  227 
nerve  supply,  238 
openings,  232 
relations,  237 
section,  212 
veins,  238 
Phlebitis  cf  ophthalmic  v.,  338 
Phlebotomy,  32 
Phlegmonous  erysipelas,  616 
Phrenic  n.,    60,  71,  78,  79,  149 
Pia  mater,  454 

in    hippocampal   fissure, 

546 
nerve  supply,  455 
Pillar  of  fauces,  224 

anterior,  212.  218,  250 
posterior,      212,      218, 
236.  250 
of  fornix,  anterior,  522.  516, 
529.    533.  536.  542, 
546,  556 
po.sterior,  522,  523,  536, 
546 
Pineal  body,  53^^,  516,  536.  539, 
'542,  556,  560 
peduncle,      516,      529 
536,  542,  556 
gland,     538.         Mde    Pineal 
Body. 
Pingueculic,  652 

Pinna,   399,   601,   660,   665,  398, 
405,  661 
action,   665 

blood  supply,  400,  665 
cartilage,  665 
dermoid  cyst,  400 
development,  400 
frost-bite,  400 
gangrene,  400 

intrinsic  muscles,  401,  663 
ligaments,  400 
lymphatics.  403,  665 
nerve  supply,  403,  665 
sebaceous  cyst,  400 
skin,  660 
Pituitary  body,  459,  343,   458, 
516,  539.  552,  565,715 
fossa,  diaphragm,  717 
memljrane,  300 

nerve  .supply,  303 
Platysma   myoides  m.,    31,    30, 
177,  621,  627 
action,  31 
blood  supply,  31 
insertion,  31 
nerve  supply,  31 
origin,  31 
Plexus,    choroid.    454,    .526,   544, 
519.523,  533,536,546, 
565,  569 
of  nerves,  axillary,  148.     Vide 
I' lex  us    of     Nerves, 
Brachial, 
basilar,  715 
brachial,    60,     148,     51, 
71,  149,  208 
line  for,  67 
operation  to  expose, 

208 
stretching,  209 
oervical,  4H,  65,  44 
branches,  48 


Plexus    of    nerves,   cervical,   de- 
scending   branch, 
45,  51,  208 
dissection,  38,  65 
superficial  branches, 

38 
s  u  p  r  a  -  a  c  r  o  m  i  a  1 

branch,  34 
s  u  p  r  a  -  c  1  a  v  i  eular 
branch,  34 
infra-orbital,  669,  675 
pharyngeal,  81,  116,  231 
subtrapezial,  66 
tympanic,  426 
vertebral,  85 
of  veins,  pterygoid,  687 
parotideus,  670 
Plica  semilunaris,  651,  649 
Pneumogastric  n.,   7(>,   466,   729, 
39,  41,  78,  79,  164, 
539.    r/(/f  Tenth  Cra- 
nial Nerve, 
branches,  81 

cardiac     branches,     cer- 
vical, 83 
ganglia,  76 
relations,  76 
Poisoning,  lead,  214 
Pole  of  eyeball,  anterior,  357 

posterior,  357 
Politzer's    method     of    inflating 

middle  ear,  411 
Polypi,  nasal,  301 
Polypus  of  frontal  sinus,   311 
Pomum  Adami,  273 
Pons  tarini,  460 

Varolii,  460,  549,  458,  516, 
539,   552,   560,  565 
dissection,  549 
hemorrliage,  550 
nuclei,  550 
position,  455 
relations,  549 
Portio  dura,  466 
mollis.   466 
Porus  opticus.  362,  380 
Post-central     convolution,      486. 
Vide  Parietal  Convolution, 
Ascending, 
fissure,  4K5,  474 
Postero-lateral  fontanel,  584 
Post-olivary  fissure,  554 
Post-parietal  convolution,  489 
Post-pharyngeal  abscess,  232 
Pouch,  glosso  epiglottidean,  216 
laryngeal,  269 
pharyngeal,  26 
Precentral  fissure,  481,  474,  477, 
480 
line.   .508 
Precuneus,  516 

convolution,  489 
Prefrontal  region  of  brain,  499 
Preoccipital  notch,  476 
Presbyopia,  391 
Preservation  of  brain,  717 
Pretracheal  fa.seia,  47.  39,  41 
Prevertebral  liraneli  of  ascending 
pliaryui;i-al  a.,  97 
fascia,  46,  39,  41 
muscles,  155,  152 
Princeps  cervicisa.,  95,  133,  137 
anastomosis,  95 


INDEX. 


763 


Process,  ciliiirv,  374,  360,  365 
mastoid,  ."ii)l 

Dluratidii  upon,   T-HS 
of  incus,  418 
of  niallius.  418 
verniifonn,     of     ocivbelluni, 

oui,  :m-> 

Processes  of  tluia  inater  of  brain, 

717,  714 
Processus  bievis,   l-Jo,  409 
caudatus,  4(K(.  401.  663 
e    cereliello   ad    testes,    ■'i43. 
Vide  I'edunele  of  Cerebel- 
lum, iSuperior. 
gracilis,  4-J:i,  409 
Profunda  cei'vicis  a,.,   147,   133, 
137.       Vide  Cervical    Artery, 
Deep. 
Proniontorv    of   nienibrana    tym- 

pini,  4-J(l 
Protuberance,  external  occipital, 

25,  .ii)l 
Pnissak's  chamber,   409 
Pterion,  .".-i-i,  506 
Pterygoid  a.,  iw:!.  678 

external,  (i-^  I,  682 
internal,  6-<l,  682 
lobe  of  parotid  nUind,  (;.">(! 
muscle,  external,  (>7!t,  678 
.action,  (M) 
blood  supply,  680 
insertion,  679 
nerve  supply,  680 
orifiin.  (!7!) 
relations.  (i-<0 
internal,  (i~(>,  303.  678, 
686.  690 
action,  (iso 
blood  supply,  680 
insertion,  6.80 
nerve  supply,  680 
origin,  680 
relations.  Cr^O 
plexus  of  veins.  6^7 
Ptervgo-maxillarv  ligament,  231, 
637,  229  ' 
region,  H7i>,  678 
abscess,  692 
contents,  679 
dissection,  676 
hemorrhage  into,  692 
lymiiliatics,  687 
nerves.  687 
veins.  687 
Pterygo-palatine  a.,  684,  682 
foramen,  693 
nerve,  698 
Pulley    for   superior  oblique  m., 

33l".  334.  632 
Pulsation  in  jugular  vein,  exter- 
nal, 32 
of  (luni  mater  of  brain,  711 
of  innominate  a.,  18 
of  ophthalmic  v.,  338 
of  or) lit,  338 
Pulvinar,  .')3-<.  539 
Puncta    lacbrvmalia,    594,     648, 

346.  632.  649 
Pupil.  367.  369 

.\rgyll  Uobertson,  367 
Pupillary  membrane.  367 
Purulent  conjuctivitis,  361 
Pus  in  mastoid  disease,  423 


Pus  in  otitis  media,  423 
Pyrauii<l  of  men\brana  tympani, 
420 
of  middle  car,  412 
Pyramidal    tnict  of    nu'dulla  ob- 
longata, 552 
Pyramidalis  na-si  ni.,  626,  627 
action,  629 
insertion,  626 
nerve  supply,  629 
origin,  626 
relations,  62(1 
Pyramid.s,  deeuss;ition,  458 
of  cerebellum,  .■)(i2 
of  medulla  oblongata,  554 
anterior,  458 
decussation,        553, 
554,  552 

Q. 

Quadrate  convolution,  489,   488, 
497 
lobe  of  cerebellum,  ,561,  560 
of  cerebrum,  516 
Quadratus  menti  m.,  (i3().       ]'ide 
Depressor  Labii  Inferioiis  Mus- 
cle. 
Quinsy,  225 


Ramus  subcutaneus  malae  n.,  694 
Raninea.,  92,  114,  105,  221 

iana.stomosis,  114 
E.annla,  114,  216 
Raplie  of  corpus  eallosum,  517 

of  pharynx,  229 
Recess  of  faiices,  224,  239 
pharyngeal,  232,  233 
spheno-ethmoid,    of    Meyer, 

229 
tonsillar,  224 
Recessus  epitynipanicus,  407 
Recti  m.'s,  conniion  tendon,  infe- 
rior, 347 
sujjerior,  347 
Rectus  capitis  anticus  major  m., 
156,   78,   79, 
152 
m.,  action,  1,56 
m.,      insertion, 

1.56 
m.,  nerve  sup- 
ply, 156 
m.,  origin,  156 
minor  m.,  156,  152 
m. .  action,  l.">() 
m.,      insertion, 

156 
m.,   nerve  sup- 
ply. 156 
m.,  origin,  l."i6 
lateralis  m.,  156,  152 
action,  1,56 
insertion,  156 
nerve     supply, 

156 
origin,  1.56 
muscle,  external.  342,  321, 
326.    330,    334. 
339 
action.  342 


Rectus  capitis  muscle,  external, 
insertion,  342 
nerve  sujijily,  342 
origin.  312 
inferior,   316,   347,  339, 
632 
action,  347 
insertion,  347 
nerve  supj)ly,  347 
origin,  347 
internal.  :'.  12.  326,  330, 
334,  339 
action,  312 
insertion,  312 
nerve  supply,  342 
origin,   3  12 
superior,  331.  320,  326, 
330.   334,    339, 
346,  632 
action,  331 
in,sertion,  331 
nerve  sujijily,  332 
Recurrent  branch  of  lacrvmal  a., 
336 
laryngeal    n.,    (<2,    127,    71, 

78,  79 
ner\e  of  fourth  cranial,  326 
Red  nuelius.  ,5,53 
Rellected  portion  of  conjunctiva, 

651 
Reflex  iris,  368 
Refracting  media  of  eye,  361 
Region  of  brain.  Broca's,  503 
occipito-angular,  203 
liiefiontjil,  499 
silent,  499 
Reid's  ba.se  line,  507.  506.  589 
Keil,  island,  470,  4S1,   5-ls,   471, 
483,   546,  565,  569 
gyri  oiierti,  471 
Reissner,  menibiane,  432 
Removal  of  bi-ain,  712 

of  Gasseriaii  ganglion,  731 

structures  involved, 
731 
Resection,     Gasseiian     ganglion, 
199 
of  dental  n..  inferior,  200 
of  infra-orbital  n.,  199 
*    of  lingual  n.,  205 

of  nuixillary  n.,  inferior,   199 

superior,  199 
of  spinal  accessory  n.,  58,  205 
Respiratory  jmrtion  of  nasid  fossae, 
300 
nerve  of  Bell,  external,  153 
Iv'i'stifdiin    body.    465,    554,    557, 

536.  542,  556 
Kctiua,  3S0.  360,  381 
blind  sjiot.  li-d 
blood  supph,  :!-ll 
central  a..  3':;i;.  360,  384 
vein.  360,  384 
Retinal  a.,  381 

veins,  3<.'>.  381 
Retrahens  aurem  m.,  60.5,  627 
action,  605 
inserti(ui.  605 
nerve  supply,  605 
origin,  605 
Ketzius,  foramen,  441,  544 
Kliinolitlis,  300 
Rhinoplasty,  285 


764 


INDEX. 


Rliinoscopy,  anterior,  307 

posterior,  308 
Khoiiiboiil  u.,  149 
Ridges,  superciliary,  588 

temporal,  592 
Rima  glottidis,  248,  26fi,  267 
Risorins  m.,  31,  (534,  627 
action,  634 
insertion,  (534 
nerve  supply,  634 
origin,  634 
Risus  sardonicus,  634 
Rivini,  notoh,  416 
Rcident  ulcer  of  nose,  285 
Rolando,  Ussure,  475,   474,  477, 
480,  516 
line,  507,  506 
funiculus,  554,  557 
tubercle,  557 
Rostrum  of  corpus  callosum,  517, 

488,  497,  546 
Rotation  of  cornea,  348 
Rouge's  operation,  300 
Rupture  of   membrana  tympaui, 
419 

S. 

Sac,    lacrvnial,    352,    594,     321, 
350,  355,  653 
abscess,  644 
larj'ngeal,  269 
Saccule,  431,  437,  439 
Saccus  endolympbaticus,  437 
Sagittal  section  of  brain,  567 
of  eyelid,  353 
suture,  573,  588 
Salivary  duct,  oljstruction,  114 

fistula,  658 
Salpingo-pharyngeusm.,  245,243 
Santorini,  cirtilage  of,  275 
fissure,  666,  401,  663 
muscle,    634.      Vide  Risorius 
Muscle. 
Sarcoma,   melanotic,   of  choroid, 
379 
of  dura  mater  of  brain,  711 
Scala  media,  432,  437,  439 
tympani,  432,  436 
v'estibuli,  432,  436 
Scalene  ra.,  posterior,  39 

tubercle,  154 
Scalenus  anticus  m.,  153,  39,  71, 
78,  79,129,152 
action,  154 
insertion,  153 
nerve  snjiply,  154 
origin,  1.5,3 
relations,  1,53 
medius  m.,  151,  39,  50,  71, 
129,  152 
action,  154 
insertion,  154 
nerve  .supply,  154 
origin,  154 
relations,  154 
posticus  m.,  154,  129,  152 
action,  151 
insiM'tion,  154 
nerve  supply,  154 
origin,  154 
Scalp,  587,  601 
abscess,  617 


Scalp,  areolar  tissue,  616 

arteries,  588,  605,  608,  613, 

640 
congestion,  015 
dis,section,  601 
fascia,  602,  603 
hematoma,  617 
inflammation,  617 
layers,  601,  599 
lymphatics,  612,  703 
mobility,  616 
muscles,  613,  627 
nerves,  611,  609,  613 
skin,  602 
tumors,  5>t7,  616 
veins,  ()(t6,  35,  645 
wounds,  602,  616 
Scalping,  616 
Scaphoid  fossa,  660 
Scapular   a.,    posterior,    59,    146, 
70,  133 
anastomosis,  146 
vein,  posterior,  70 
Schlemm,    canal   of,    362,    360, 

365.  384.  394 
Schneiderian  membrane,  300 

nerve  supjilv,  302 
Sclera,  361,  360,  365,369,  376, 

381,  394 
Scleral  sulcus,  362 
Sclerotic  coat,  361 

portion  of  conjunctiva,  358, 
651 
Sebaceous  cyst  of  pinna,  400 

gland  of  cilium,  353 
Second  cervical  n.,   anterior  divi- 
sion, 71,  78 
cranial  n,,   402,    727,      Vide 

Optic  Nerve, 
sight,  396 
Section  of  brain,  coronal,  567 
.sagittal,  567 
of  cerebrum,  546 
ofciliarj-  region   of  eyeball, 

365 
of  eye,  360 
of  eyelid,  353 
of  tongue,  221 
trans\'erse,  of  neck,  39 
Sections  of  brain,  567 
Semicircular  canal,  ampulla,  432 
external,  430,  427,  430 
posterior,      427,      430, 

439 
.superior,       427,       430, 
439 
canals,  431,  427 

membranous,  437 
Semispinalis  colli  m.,  39 
Sensori-motor  area  of  brain,  500 
Sensory  areas  of  brain,   499,    501 
nerves  of  parotid  gland,  657 
root  of   lenticular  ganglion, 
335 
Septa  orbitale,  653 
Septal  branch  of  nasal  n.,  335 

of  .Meckel'sganglion,  698 
cartil.-ige  of  nose,  293,  291 
Septum,  artery  of,  307 
linguic.  111,  220 
lucidum,    522,     516,      523, 
536,     542,     546,     556, 
565 


Septum,  nasal,   294,   236,   291, 
306 

deviation,  294 
perforation,  294 
of  nose,    arterv,    643,     613, 
640 
lieiiiorrbage    from, 
(;43 
orbitale,  320 
Serralus  maginis  m.,  50,  71 
Sesamoid  cartilages  of  nose,  293 
Seventh  cervical  n.,  anterior  di- 
vision, 71,  78 
cranial    n.,    465,   728,    458, 
715 
origin,  552 
Sheath,  carotid,  66 

contents,  73 
Shrapnell's  membrane,  419,  418 
Sight,  second,  396 
Sigmoid  sinus,  720,  715 
course,  592 
thromliosis,  423,  511 
Silent  region  of  brain,  499 
Sinking  of  eyeball,  357 
Sinus  ala?  i)ar\  le,  724 

cavernotis,  relation  to  Gasse- 
rian  ganglion,  725 
section.  343 
cervicalis,  26 
circular,  726,  714,  715 
circularis  rectii,  471 
ethmoid,   315.       ]'iile    Cells, 

Ethmoid, 
frontal,  30-^,  298,  314,  339, 
355,  653,  705,  709 
congestion.  311 
empyema,  311 
fractme.  311 
polypus,  311 
pus,  311 
inferior     longitudinal,     724, 
714 
petrosal.  726,  714,  715 
lateral,  720,  714,  715 
course,  592 
divisions,  720 
line,  723,  721 
operation  to  expose,   510 
thrombosis,  511,  720 
tributaries,  720 
longitudinal,    inferior,     724, 
714 
superior,  719,  714,  715 
course,  592 
line,  719 
wound,  719 
maxillary,    312.       Vide    An- 
trum of  High  more, 
occipital,  724,  715 
of  chamber  of  eve,  anterior, 

391 
of  external  auditory  meatus, 

403 
of  larvnx,  266 
of  Morgagni,  231,  229 
petrosiil,    inferior,    726,  714, 
715 
superior,  726,  715 
thrombosis,  723 
pvriformis,    237,    248,    218, 

236.  250 
sigmoid,  715 


INDEX. 


765 


Sinus,  sigmoul,  conrsp,  r>!)2 

throiuliosis.    I'.>:!,  511 
sphenoiil.  :>15,  291 
sphen()-|Kiiictal,  7"J4 
strait;ht,  VK.  7J4,  714 
SHperiof    iDii^ituilinal,     719, 
714,  715 
I'our.sf,  .■>;):.' 
lino,  71!) 
wounil.  719 
petrosiil,  "rUS.  715 
transverse,  726,  714.   715 
Sinuses,  cjiveriions,  ~:l'\  715 

of  dura   mater  of  Iiraiii,  ~\A, 
714,  715 
lie  111  orrliage 
from,  719 
of  frontal  l)one,  ."lUl 
Sixth  cervical  n. ,  149 

anterior  division,  39, 
71,  78 
cranial     n..     :ill.     Ifi.i,    728, 
326.  339.  343,458,715 
Skin  of  eyelid,   353  / 

of  face,  025  / 

of  neck,  17,  26 
of  nose,  285 
of  pinna,  660 
of  scalp,  602,  599 
Skull,  arteries,  573 

base,  dislocation,  579 

fracture,  5iS5 
blood  supply,  617 
bones,  development,  584 
bregma,  573 
fontanels,  5S4 
fracture,  692,  707 
fractures,  584 
lambda,  573 
sutures,  .573 
vault,  fracture,  585 
Slender  lobe  of  cerebellum,  560 
Slit,  interpaljiebral,  648 
Smegma  prteputii,  628 
Smell,  center,  503 
Snorin;;;,  637 
Socia  parotidis,    656,    659,    613, 

627 
Soft  palate,  23^1 
Space,  crico-thyroid.  24 
intercrural,  459 
interpe<luncular,  4.59 
of  Tenon.  324,  395,  321 
perforated  anterior,  459,  458 

posterior,  461),  458 
subarachnoid,  441 

aspiration,  442 
subdural,  441 
sni)ra-sternal      intra-aponeu- 

rotic,  of  Griiber,  37 

supravaginal  Ivmpli,  321 

Spaces  of  Fontana,"362,  392,  365 

Spheno-ethmoid  recess  of  Jleyer, 

299 
Sphenoid   cells.    315,    212,  296, 
298.  309 
tissure,  nerves  in,  342 

structures        traversing, 
343 
sinus,  315,  291.     Vide  Sphe- 
noid Cells. 
Sphenoidal  cells,  714 
Spheno-niandibular  ligament,  574 


Spheno-muxillary  division  of  in- 
ternal maxillary  a.,  683 
fo.s.si,  69:! 

contents,  693 
foramina,  693 
Spheno-iialatine  a.,  307,  G84,  682 
foraiiiiMi,  693 
ganglion,  (i97 

nerve,  694,  303.  690,  695 
Spheno-jKirietal  sinus,  721 
Sphincter  oculi  m.      (((/(Orbicu- 
laris Palpebrarum  Muscle, 
oris   m.,    634.      ]'itlf  Orbicu- 
laris Oris  Muscle. 
Spina  helicis,  400 
Spinal  acces.sory  n.,   57,  466,  729, 
"39,   51,    71,  78, 
79,    539.        Vide 
Eleventh    Cranial 
Nerve, 
line  for,  20,  67 
operation  to  expose, 

182 
resection,  58,  205 
artery,    anterior,   449,    444, 
452 
lateral,    of   vertebral   a., 

143 
posterior,  449,  444 
Spiral  canal,  432 
Splenium  of  corpus  eallosum.  517, 

488,  497,  516.  523,  546 
Splenius  m.,  39.  78,  79 

capitis  m.,  50,  71,  152 
S(iuint,  convergent,  ;!73 
Stapedius  m.,  425,  422 
action,   425 
insertion,  425 
nerve  supply,  425 
origin,  425 
Stapes,  424,  405,  409.  422 

crura,  424 
Staphyloma  of  cornea,  364 
Steuson's  diut,   658,    609,    613, 
621,  627,  640 
course,  658 
divisions,  lioO 
line,  27.  623 
relations,  658 
Stephanion,  592 
Sterno-clavicular  joint,  18 
Sterno-cleido-mastoid  m.,  17,  48. 

]'ide  Sterno-ma.stoid  Muscle. 
Sterno-hyoid  m.,  12n,  39,  50,  71, 
78,  117 
action,   121 
blood  sui^ply,  121 
insertion,  120 
nerve  supply,  120 
origin,  120 
relations,  120 
Sterno-ma.stoid  a.,    inferior,  146, 

70.  78 

middle.   5^^.    91,  59,  70, 

78,  177 
superior,  95.  70.  78 
muscle,   17,  48,  39.  41,  50, 

71,  78,  79,  117 
action,  53 

blo(Kl  su]iply,  53 
coniraction,  ,53 
insertion,  53 
nerve  snpjily,  53 


Sterno-nuistoid  mu.scle,  origin,  48 

nerve,  71 
Sternothyroid  m.,  121,  39,  50, 
71,  78.  117 

,iction,  121 
insertion,  121 
nerve  su])ply,  121 
origin,  121 
relations.  121 
Stertorous  breathing,  637 
Stilling,  canal,  385 
Stirrup,  423.     1 7(/c  Stapes. 
Strabismus,  348,  373 
Straight  siiuis,  532,  724,  714 
Stretching  brachial  nerve  plexus, 
2(19 
facial  nerve,  205 
Stria  terminalis,  ,526.     Vide  Tnenia 

Semicircularis. 
Stria'  aciisticje,  517 
auditory,  547 
longitudinales,  517,  513 

lalerales,   517 
mednllares,  542,  556 
Structure  traversing  sphenoid  fis- 
sure, 343 
Stylo-glossus   m..    Ill,   220,   79, 
105.  109 
action,  111 
blood  supply.  111 
insertion.  111 
nerve  supply.  111 
origin,  11 1 
Stvlo-hvoid  branch  of  facial  n., 
669 
ligament,    ll.^i.   576.  577 
nuLscle,    98,    50,    71,    105, 
177 
action,  103 
blood  su])ply,  103 
insertion,  103 
nerve  sui)ply,  103 
nerves,  51 
origin,  103 
Stylo-niandibular  ligament,  574 
Stylo-mastoid  a..  96 
Stvlo-ma.xillarv  ligament,  46,  63, 

574,  576,  577 
Stvlo-pharyngeus    m.,     115,    79, 
105,  229 
origin.  115 
Subarachnoid  cisterns,  441 
space,  441 

aspiration,  442 
Subclavian    arteries,     differencses 
between.  128 
artery,   23.   60,  127,  166.  50. 
70.  78,  79.133.208 
branches,  136.  87 
compression,  23 
diagram,  87 
first  portion,  129,  164, 
174 
ligation,   135, 
1G6 
irregularities,  170 
left,  128 

relations,  128 
ligation,  collateral  circu- 

l.itinn,  135,  133 
line,  20,  67 
right,  127 

relations,  127 


766 


INDEX. 


Subclavian  artery,  second  portion, 
131 
ligation,     135, 

106 
relations,  131 
third  portion,  131 
guide,  175 
ligation,      132, 

166,  169 
ligation,  collat- 
eral   circula- 
tion, 170 
operation  to  ex- 
pose, 167 
relations,     131, 
166 
variations,  132 
triangle,  54,  59,  55 
contents,  60 
dissection,  59 
vein,   60,   35,    70,    78,    79, 
129,  174,  645 
Subconjunctival  hemorrhage,  358 
Subdural  space,  441 
Sublingual  a.,  115,  78,  79,  105 
anastomosis,  115 
bursa,  216 
gland,  113 

blood  supply,  114 
nerve  supply,  114 
relations,  113 
Submaxillary  a.,  93 
ganglion,  113 
glaud,  103,  113,  51,  177 

relations,  103 
lymphatic  glands,    63,    702, 

157 
triangle,  54,  63,  55 
contents,  63,  98 
dissection,  63 
Submental  a.,  93,   50,  70,  105, 
682 
relations.  93 
vein,  35,  645 
Suboccipital  Ivnipliatic  glands,  702 
Snbpariotal  tiisure,  4S9,  496,  488, 

497,  516 
Subpubic  ligament,  616 
Subscapular  a.,  133 
nerve,  lower,  149 
middle,  149 
upper,  149 
Substantia  fi-rrnginea,  547 
nigra,  .553 
liropria,  363 
Subthalamic  body,  5.53 
Subtrapezial  nerve  plexus,  66 
Sulcus  centralis  insuke,  470,  471 
Keilii,  470 
cerebelli,  superior,  560 
choroideus,  538 
circnlaris  Keilii,  470 
nu'dian  longitudinal,  542 
of  brain.      Vide  Fis,sure. 
olfactory,  456 
orbital,  456 
scleral,  362 
triradiatc,  456 
Superficial  cervical  m.,  31 
Superlicialis  colli  n.,  45 
Superior  maxilla,  excision,  579 
lines  of  incision, 572 
fracture,  586 


Supernumerary  auricles,  400 
Supra-acromial  branch  of  cervical 
plexus,  34 
of  supra-scapular  artery, 
146 
nerve,  45 
Supra-clavicular  branch  of  ceivi- 
cal  plexus,  34 
fossa,  18,  21 
nerve,  45 
triangle,  .59 

dissection,  59 
Supra-liyoid  aponeurosis,  98 
Supra-marginal  convolution,  486, 

489,  474,  477 
Supra-maxillaiv  lirancb  of  facial 

n.,  070,  609^  613,  620 
Supra-meatal    triangle    of     Mac- 

Ewen,  415 
Supra-orbital  arches,  593 

artery,   :'.:!6,   (;(I5,   197,  334, 
603,  608,  613,  620, 
640 
anastomosis,  336,  605 
branches,  336 
operation  to  expose,  197 
foramen,  595 
margin,  310 

nerve,   327,    611,    197,    326, 
339,  609,  613,  620 
neurectomy,  611 
operation  to  expose,  196, 
197 
notch,  316,  595 
vein,  35,  645 
Supra-parietal  convolution,  474 
Snpra-rinial     portion    of    larvnx, 

296 
Supra-scapular   a.,    00,    145,    50, 
70,     78,     79,     129, 
133,  174 
branches,  146 
relations,  145 
nerve,  153.  51.  71.  149 
vein,   60,   35,    50,   70,   167, 
645 
Supra-sternal   branch  of   cervical 
plexus,  34 
fossa,  18,  21 
intra-aponeurotic    space      of 

Griiber,  37,  40 
nerve,  45 
Supra-trochlear  n.,  327,  611,  326, 
339,  609,  613 
neuri'ctdmy,  611 
Supra-vaginal  lymph  space,  324, 

395,  321 
Surface   anatomy   of  neck,    back 
of,  25 
markings  of  neck,  17,  21 
of  auricle,  001 
of  cranium,  587,  589 
of  ear,  701 
of  eye,  593 
of  face,  592 
of  pinna,  701 
Suspensorv  ligament  of   eyeball, 
'  324 

of  lacrvmal  gland,  328 
of  lens,  360.  372 
of    malleus.     424,     409, 
413.  422 
Suture,  coronal,  573,  588 


Suture,  frontal,  573,  588 
lambdoid,  573,  588 
parietal,  573 
sagittal,  573,  588 
transverse  occipital,  573 
Sutures  of  skull,  573 
Sylvian  a.,  446 

ventricle,  525.        J7(/e  Fifth 
Ventricle. 
Sylvius,  aqueduct,  537,  483,  516, 
528.  529 
fissure,   450,   470,  471,  474, 
477.  569 
line,  .507,  506 
Symblepharon,  3(Jl 
Sympathetic,  n.,  78,  79 

cervical  portion,  83 
Synechia,  annular  posterior,  395, 
394 
anterior,  367 
posterior,  367 
Synovial  mendjraue  of  temporo- 

maxillary  articulation,  574 
Swallow's  nest,  562 
Sweat  gland  of  Moll.  353 


Tactile  sensation,  area,  500 

Tjenia  violacea,  547 

Tsenite  hippocamjii,  522,  526 

semicircularis,  52(i,  538,  519, 
523,  536,  542.546,556 
tectse,  517 
Tapping  lateral  ventricles,  442 
Tarsal  cartilage,  593,  052 
ligament,  external,  630 
internal,  030 
Taste  center,  503 
Tears,  328 

course,  352 
Teeth,  213 

test,  of  Hutchinson,  214 
Tegmen  antri,  412 

destruction,  420 
tynipani,  422 

destruction,  420 
Tegmental  nucleus,  553 
Tegmentum,  460 

of    crus    cerebri,    553,    488, 
497 
nuclei,  553 
Tela  choroidea,  inferior,  544,  516 

superior,  531 
Temporal  a.,  (idO,  193 

anterior,  OtlO,  603,  608, 

613,  640 

dee|i.      0S3,      678, 

682,  686 

middle,  608,  613,  620, 

640 
operation  to  expose,  193 
posterior,  000,  603,  608, 
613,  640 
anastomosis.  006 
deep.  683.  678,682 
superficial,    133.    608, 
613,    620.    621. 
640.    678,    682, 
686 
ligation,  195 
branch  of  facial  n,.  012,  669, 
609,  613.  620 


INDEX. 


767 


Temporal    biiinth   of  orbitjil   ii., 
;{51,   (il-J,  674,   609,  613, 
620 
couvoliitioii.    iiifrnm.     474, 
477 
muUllr,  474,  477 
siiiMiior.  474,  477 
division  i>f  faii:il  ii,,  GliG 
fascia.  (JH.  620 

abst'ess  lunieatli,  618 
density,  (il8 
relations,  (il.'? 
fissure,  middle,  474,  477 

suiwrior,  474 
lobe,  JHl,  lill,  471 

inferior  surfaee,  494 
landmarks,  oClU 
lobes,  4-j(> 
Ivniphatios,  (il.^ 
iniiscle,  (ir>,  321,  621,  678. 
686 
action,  fii) 
blood  supply,  625 
ins<Mtion,  (>",*."> 
nerve  supply,  625 
ori^tin,  (>"J."> 
nerve,  anterior,  (UJ,  686 
posterior,  lil-J,  678 
supertieial,  68S 
iiers'es,  deep.  6i^7 
region,  6'.'.">.  621 
ridges.  .")!1'2 
vein,  50,  70,  319 
middle.  35.  645 
superliei:d.      35.      613, 
620    645 
Teniporo-faeial  ii.,  6i>i) 
bniuclies,  609 
Temporo-malar  n..  3.'il.  694 
Temporo-maxillarv   articulation, 
b7:i.  576.  577 
blood  supply.  .i74 
interartieular  fibro-carti- 

lage.  ,574 
ligaments,  .">7:{ 

ciiwnlar.  576.  577 
internal  lateral,  574 
movements,  r-t'-i 
nerve  supply,  .■i74 
synovial  meinlirane,  574 
vein,  "35   621,  695 
Temporo-splienoid  abscess,  511 
trepbining.  511 
convolution,     inferior,     495, 
494 
middle,  492.  494 
superior.  4!»2.  494 
fissure,    inferior.     I'.i2.    488, 
494.  497 
middle.   192.  494 

line.  51(1.  506 
superior.  492.  494 
line.  510.  506 
lobe,    4.56,    if*\.     191.    458, 
565.      fide  Temporal 
Lobe, 
landmarks.  ,509 
Tendo  oculi.  .594,  6:i().  652,  350 

l)ali>ebranini,  6I!0 
Tendon,  central,  of  perineum,  590 
common,  of  recti  miLscle.  in- 
ferior, 347 
superior,  :i47 


Tendon  of  unio-liynid  m,,  39 

tensor  tympani,  409 
Tenon,  capsiile,  H21.  :M2,  320 
eajisula.  321 
space,  :{2I,  :!95.  321 
Tenotomy  in  torlieollis,  H7 
Tensor    palati     m.,     245,    303, 
690 
action,  245 
insertion.  245 
origin.  245 
tarsim.,63:>,  321.346,355, 
632,  653 
action,  (iol 
insertion,  (iH."} 
nerve  supply,  634 
origin.  63:! 
relations.  (>'■)'■'> 
tympani  m..  42.5,  405,  422 
action,  425 
in.scrtion,  425 
ner\  e  supply,  425 
origin.  425 
tendon.  409 
Tenth  cranial   n..  76.    Iiu:.  458, 
542,  556 
origin,  552 
nerve,  729,  715 
Tentorium    cerebelli,     4.55,    712, 

717,  71S,  714 
Terminal  biancb  of  anterior  eth- 
moid a..  I!37 
Testes,  o4:>,  542,  556,  560 

brachia,  541! 
Tetanus,  231 

Thalamus,    optic,   526.  53X,  519, 
523,  542,  546,  552, 
569 
puhinar,  539 
tubercle,  anterior,  538 
posterior,  538 
Third  cervical   n..  anterior  divis- 
ion, 71,  78 
cranial  n.,  341,  402,727,326, 
458.    Title  Oculo- 
motor Nerve, 
origin,  552 
ventricle.     .5.32.     516,    528, 
529,  536,  556,  569 
Thoracic  a.,  lung,  123 
sui)eri(jr,  133 
duct,  12f<,  100,  129 

relations,  131 
nerve,  external  anterior,  149 
first,  149 

anterior  division, 79 
internal  anterior.  149 
]iosterior.    or  long,   153, 
51,  71,  149 
Thrombosis  of  lateral  sinus,  511, 
720 
of  petrosal    sinus,    superior, 

423 
of  sigmoid  sinus,  423,  511 
Thyro-ar>tenoid  ligaments,  supe- 
rior, 260 
Thyro-arytenoidens  m.,  261,  259 
action,  261 
insertion,  261 
nerve  supply,  261 
origin,  201 
Thyro-epiglottidean       ligament, 
270 


Thyro-epiglottideus  m.,  261 
action,  261 
nerve  supply,  261 
Thyro  glo.ssid  duct,  125,  216 
Thyro-liyoid  bursii,  2.55 

ligaiMiMit,  2,55,  254,  263 
nicinliiane.    2.55,    123,   212, 

251,  254,  263 
nnisele,    121,    50,     71,     78, 
177 
action,  121 
blood  supply,  121 
insertion,  121 
nerve  supply,  121 
origin,  121 
relation.s,  121 
Thyroid  a.,  inferior,  (il,  144,    78, 
129,    133,     174, 
229 
anastomosis,  144 
branches,  144 
irregularities,  179 
ligation,    145,    179, 

177 
line,  20.  67 
operations  to  expose, 
174 
superior.     S6,     50,     70, 
78,     105,      123, 
133,  177,  251 
irregularities,  IhH 
ligation.  1S7,  177 
line,  20,  67 
axis,  144,  78,  79,  133,  174 

branches.  114 
body,  39,  78 

cartilage,  21!.  273.  123,  251, 
254,  258.  259,  271 
fracture.  274 
ossilieation.  274 
gland,    23.    122,    123,    129, 
251 
arteries,  126 
capsule.  126 
in  tiacbeotoniy,  122 
isthmus,  251 
nerves,  126 
relations,  122 
structure,  122 
veins,  120 

inferior.   78,    79,     123, 

164.  251 
middle,  35,  70,  645 
superior,     91,     35,     70, 
645 
Thvroidea;  inia  a.,  126,  133 
Tli'vroidectomv,  126 
Tie  c<invulsif.'205 

douloureux',  700 
Tissue  of  evelids.  652 
Tongue.  216.  212 
apex,  210 
arteries,  105 
atropby.  220 
base,  216 
blood  supply,  223 
dissection.  216 
dorsum,  216,  218 
excision,  223 
glands,  219 
in  anesthesia,  223 
lymi)lialics,  223 
muscles,  219 


768 


INDEX. 


Tongue,  muscles,  dissection,  108 
extrinsic,  219,  109 
intrinsic,  320 
nerve  supply,  223 
paralysis,  220 
root,  216 
section,  221 
tip  of,  216 
Tongue-tie,  115,  216 

operation.  115,  215 
Tonsil,  224,  218,  239 
amputation,  225 
arteries,  105 
hypertrophy,  225 
lingual,  219 
lymphatics,  225 
malignant  growths,  226 
of  cerebellum,  562 
of  Luschka,  pharyngeal,  232 
pharyngeal,  233 

hypertrophy,  232 
relations,  225 
tubal,  411 
Tonsillar  a.,  93 

branch  of  dorsalis  linguae  a. , 
105 
of  facial  a.,  105 
of  glosso-pharyugeal  n., 
119 
recess,  224 
Tonsillitis,  225 
Tonsils,  blood  supply,  224 
crypts,  224 
nerve  supply,  225 
veins,  225 
Tophi,  400,  665 
Torcular  Herophili,  591,  719 
Torticollis,  53 
spasmodic,  58 
tenotomy,  37 
Touch,  center,  503 
Trabecula;,  647 

Trachea,  24,  282,  39,   41,    123, 
129 
cervical  portion,  relations,  282 
Tracheal  ))ranch  of  inferior  thy- 
roid a.,  145 
Tracheloniastoid  m.,  152 
Tracheotomy,  24,  282,  279 
incision,  21 
thyroid  gl;md  in,  122 
veins  in,  37 
Tract  of  medulla  oblongata,  lat- 
eral,    554,     552, 
556 
pyramidal,  552 
olfactorv.  '  456,     462,      303, 

458,  539.  690 
optic,  462,    458,    539,    552, 
565,  569 
diagram,  463 
uveal,  367 
Tracts,  optic,  462 
Tragicus  m,,  665,  401.  663 
Trains,  399,  660.  398,  661 
Transversalis  oiilli  a.,  .59,  60,  146, 
50.      70.      78.     129, 
133,  174.  208 
vein,  6(1,  35,  50,  70 
humeri  a.,  145 
Transverse  a.,  4.50,  444,  452 

facial    a.,    6  11.     608,     613, 
620,  640.  645 


Transverse  facial  vein,  35,  678 
fissure,  467,  481.      Vide  Pre- 
central  r"'issure. 
line,  .507 
occipital  fissure,  572 

suture,  573 
sinus,  726,  714,  715 
Transversus  auris  m.,   665,  401, 

663 
Trapezius  m.,   39,   41,   50,    71, 

78,  79 
Traumatic   epilepsy,    trephining, 

512 
Trephining  in  abscess,  cerebellar, 
511 
extradural,  511 
teniporo-spheuoid,  511 
indications,  510 
in  epilepsy,  Jack,sonian,  504 

traumatic,  512 
in    extradural     hemorrhage, 

734 
in  hea<lachc,  512 
mastoid  antrum,  415 
Triangle,  carotid,  inferior,  54,  61, 
55 
contents,  01 
dissection,  61 
superior,  54,  62,  55 
contents,  62 
dissection,  62 
common,  anterior,  54 

posterior,  54 
digastric,  54,  63 

dissection,  63 
lingual,  64 

dissection,  64 
occipital,  54,  55 
abscess.  59 
contents,  57 
dissection,  57 
of  election,  63 
of  neck,  anterior,  18 

posterior,  18 
subclavian,  54,  59,  55 
contents,  60 
dissection,  59 
submaxillary,  54,  63,  55 
contents,  63,  98 
dissection,  63 
supra-clavicular,  59 

dissection,  59 
supra-meatal,    of   MacEwen, 
415 
Triangles  of  neck,  54 
diajjram,  55 
dissection.  .54 
Tributaries  to  lateral  sinus,  720 
Trifacial  n.,  465.  728,  339.   539. 
]l(h'  Fifth  Cranial  I\er\e. 
neuralgia.  698 
Trigeminal  neuralgia,  700 
TriKcminus  u.,  465.      Vidf  Fifth 

Cranial  Nerve. 
Trigonum   hvpoglossi,  547,    536, 
542,  556 
olfactiirium,  462 
omo-olaviculare,  59 
ventriculi,  .521 
Trihorned  ventricles,  518 
Tri  radiate  fissure,  456,  482,  458, 
483.    488.    497.        Vide    Or- 
bital Fissnn-. 


Triradiate  sulcus,  4.56 
Trochlear  branch  of  supraorbital 
a.,  336 
nerve,   327,   462,    543.      Vide 
Fourth  Cranial  Nerve. 
Tubal  tonsil,  411 
Tube,    Eustachian,      408,     405 
409 
blood  supply,  412 
mucous  glands,  411 
nerve  supply,  412 
occlusion,  411 
orifice,  298.  422 
relations,  411 
Tuber  annulare,  460,  549.      Vide 
Pons  Varolii, 
cinereum,  4.59,  458,  516 
valvulse  of  cerebellum,  562, 
560 
Tubercle,  carotid,  24,  152 
cuneate,  557 
Darwin's.    399,    398.    401, 

663 
of    cerebellum,      laminated, 

562 
of  epiglottis,  270 
of  optic  thalamus,  anterior, 
538 
posterior,  538 
of  Rolando,  557 
scalene,  154 
Tulierculum  acusticum,  547,  536, 

542,  556 
Tumors  of  antrum  of  Highmore, 
312 
of  scalp.  587,  616 
Turbinated  bone,  296 

inferior,  299.  309.  350 
middle,  299,  309,  350 
suijerior,  299 
bones,  necrosis,  300 
Twelfth  cranial  n.,  104,  467,  458 
origin.  552 
nerve,  729.  715 
Tympanic  a.,  683,  682,  686 

branch  of  ascending  I5har3-n- 
geal  a.,  97 
of  glosso-pharyngeal  n., 
116,  426 
plexus  of  nerves,  426 
Tympanum,  407 

anterior  view,  409 
ligaments,  424 
ner\e  sujiply,  425 
nerves,  425 


Ulcer  of  cornea,  363 

rodent,  of  nose,  285 
Ulnar  u..  149 
Umbo,  416.  418 
Uncinate  ciin\(iliitions.  495 
Uncus,  483.  488.  494.  497 
Utricle.   i:!l,  437.  439 
Uveal  tract.  3(i7 
Uvul.a.  23X,  212,  236.  239.  296 

of  cereliellum,  562,  560 

of  mouth,  224 


Vagus  n..  76,  729 
Valleeula,  218,  250 


t 


INDEX. 


69 


Valleoula  of  cerebellum,  558 

Svlvii,  470 
ValleculiB,     glosso-epiglottidemi, 

21(i 
Vallum,  219 
Valsalv;i  nietlxxl  of  inflatiug  miil- 

.Uf  ear.  411 
Valve   of    Vieiissens,    .543.       Title 

Mcdullarv  Velum,  ."^uperioi'. 
Variations  in  brain,  ,")10 
Vas  aberraiis.  art<?rv.  133 
Vascular  eoat  of  eye.  'Mil 
Vivseularit.v  of  faee,  (!17 
Vault  of  skviU,  fnicMire.  ."W.") 
Vein,  anjiular.  (imi.  35,  645 
anterior  juiiuhir,  645 
ma.\illai_v,  (i-<7,  645 
temporal    diploic,     707, 
705 
aiu'ieiilMr   |Misterior.    fK>.    35. 

50.  51.  70.  645 
centr.il,  of  retina.  360,  384 
cerebral  superior,  709 
cervical,    deep,  ilU,    117,  35, 
645 
suiHTlieial,  70 
ciliarv.    anterior,    379,  369, 

377.  384 
communieatin^.  70 
conjunctival,  384 
deep  cervical,  !)ii.  35.  645 

facial.  (;s7 
external  juf;ular.  645 

line.  623 
facial,  93.  60(1,  (144.   35.   50. 
70.    613.   620.    621. 
645 
arterial  blood  in.  647 
conimunieatious.  G47 
coarse.  (147 
deep.  <!47 
disea.se.  (147 
line.  623 
relations.  93 
transvei"se.  35.  645 
frontal.  35 
infra-liyoid.  117 
iiifniorbital.  '>7<) 
innominate.  35.  645 
left.  129 
ri-lit.  129 
internal  jugular.  645 

tiia.\illarv.  6'^7.  645 
jugular,  .interior,  'i'.i.  37.  30, 
34.  35.  39.    50.  70. 
117.  164,  174,  177, 
645 
external.  3-7.  (iO.  30.  34. 
35    39.   50    70. 
174.  208.  645 
j  uKulo-ce  plialic 

branch,  23 
line,  23,  32,  27.  623 
pulsation  in.  32 
termination  of.  l* 
internal.  i!l.  Hi.  73.  35. 
39.   41.    50.   70. 
78.     129.     164, 
174    645 
position,  18 
relations.  73 
posterior.    30.    35,    50. 
70.  208.  645 


Vein,  jufiular,  jKisterior,  external, 
37 
JH<rulo-ceplialic,  23 
labial,  inferior,  117 
linjiual,  92.  112,  35,  50,  51, 
70.  177,  645 
relations,  112 
inastoid,  37 

inaxillarv,  anterior,  687,  35, 
645 
internal.     687,    35,    50, 
70,  645 
middle  temporal.  645 

thyroid,  645 
occipital,  9,"),  35,  645 
diploic,  707,  705 
relations.  !)."> 
ophthalmic,  337.  343 
common,  33-'.  334 
inferior,  33>',  334 
phlebitis,  338 
pulsiition,  3,3"* 
superior.  33'^.  334 
orbital.  35.  645 
pharyn(;eal,  ilescendins,  97 
posterior  auricular,  35 
pudic,  internal,  61,i 
retinal,  381 
scapular,  posterior.  70 
subclavian.    60.    35,  70,  78, 

79,  129,  174.  645 
submental.  35.  645 
superlicial     temporal,     620, 

645 
superior  thyroid.  645 
supraorbital.  35.  645 
su]tra-sca)Milar.   61).    35.    50, 

70.  167,  645 
temporal,  50,  70,  193 

dijiloic,      anterior,     707, 

705 
middle.  35.  645 
superlicial.       35,     613, 
620.  645 
temporo-maxillary,  35,  621, 

645 

thvroid,     inferior,     78.    79, 

123    164,  251 

middle,  35.  70.  645 

su)>erior,  91.  35.  70.  645 

transversjdis   colli.     60.    35, 

50.  70.  645 
transverse  facial.  35.  645 
vertebral.    1  13.   35.   33,  78. 
79.  129,  137.  174,  645 
Veins,  cerebellar.    I.'il 
diploic,  704.  705 
frontal,   707,  645 

diploic.  7117.  705 
fronto-spheuoid.  707,  705 
in  tracheotomy,  37 
meninf;ea'.  73."> 
of  brain,  4.54 
of  cerebrum,  4.54 
of  external  auditory  meatus, 

407 
of  eyeball,  379 
of  evelids.  (i.').") 
of  face.  35.  645 
of  (ialen.  442.  532,  533,  714 
of  head,   645 
of  internal  ear,  437 
of  larynx,  265 


Veins  of  middle  ear,  425 
of  nasjil  cavities.  307 
of  neek.  35.  645 
of  nose,  2"'5 
of  orbit,  334 
of  pharynx,  238 
of  ptery;;oid  plexus,   687 
of  i)terygoinaxillary  renion, 

6M7 
of  scalp,  606,  35,  645 
of  .scrotum,  644 
of  tonsils,  225 
ptery;;oid  plexus,  687 
retinal,  3,-<5 
thyroid,  126 
Velum    iuli-i  po^ilum.     1.5 1.    531, 
488,     497,      516,     533, 
546.  569 
medullary,  posterior,  ,562 
superior,  543.  516,  536, 
542.560.    I Vr/,  Valve 
of  A'ieus-^ens. 
Vena  aqneductus  c<K'hlea,  437 
vestibuli,  437 
cjiva,  superior,  129.  137 
vorticosa,     .374,     379.     360. 
369,  376,  377.  384 
Venesection,  32 
Ventricle  of  Arautius.  541 

of  brain,  liftli,  .525,  488.  497, 
516,  523,  565 
fourth.   5  1  1.   516.   528, 
529,  542,  560 
floor,  536 
lateral,  518.  488,  497, 
516.  523 
boilv,      51M,      519, 

528.  569 
cornu.  auleiior,  521. 
5  2  8.     5  2  9. 
546 
middle.    .521, 

528.  529 
posterior.     521, 
5  2  8,     5  2  9. 
546 
posterior,  bulb, 
529 
cornua,  519 
dis.sectiou,  518 
tapping,  442,  511 
Svlvian.  .525 
third.    .5.32,    516,    528. 
529.  536,  542,  556, 
569 
trihomed.  518 
of  corpus  eallosum,  496 
of  larvnx,     21^.     266,    212. 
218.  250.  296 
Ventricles  of  brain.  536 
bodies.  529 
di.if;rani.  528,  529 
section.  516 
Ventriculi  trieornes.  518 
Vermiform  process  of  cerebellum, 
561 
inferior,  ,562 
superior,  561 
Vertebra  prominens,  25 
Vertebral  a..  61.  136.  419.  39.  70, 
78,     79,    129     133 
137,  152.  164    174. 
444,  452 


770 


INDEX. 


Vertebral  a.,  Iiranches,  143 

cervical  portion,  136 
guide,  176 
irregularities,  176 
ligation,  143.  175 
occipital  portion,  143 
operation  t«  expose,  174 
relations,  136,  175 
vertebral  portion,  136 
nerve  plexus,  85 
vein,   143,   35,  39,   78,  79, 
129,  137,  645 
Vertigo,  aural,  437 
Vesico-prostatic  plexus  of  veins, 

263 
A'essels  of  brain,  43"^ 
of  neck,  70,  71 
Vestibular  n,  43^!,  466 
Vestibule  of  cochlea,  427 
of  labyrinth,  431 
of  mouth,  21(1,  212 
of  nose,  285,  302 
Vicq  cVAzyr,  bundles,  522 
Vidian  a.,  684,  682 
canal,  309 

nerve.  302,  698,  303,  690, 
695 
Vieussens,  valve,  543 


Visceral  arches,  25 
Vision  centers,  503 
Vitreous  bodv,  385 

chamber"  385,  360 
Vocal  cords,  24 

false,     248,    266,    212, 

218,  250,  296 
trne,     248,     :.'(;(!,     212, 
218,  250,  296 
Vomer,  291 

Waldeyer's  glands,  353 

Weight  of  brain,  455 

Wharton's  duct,  113,  70,  71,78 

relations,  113 
Wilde's  incision,  591 
Willis'  circle,  445,  444 
Window,  oval,  420 

round,  420 
Wings  of  nose,  284 
Word-blindness,  503 
Word-deafness,  503 
Wounds  of  cornea,  363 

of  face,  647 

of  longitudinal   sinus,  supe- 
rior, 719 


Wounds  of  middle  meningeal  a., 
734 

of  jiarotid  gland,  658 

of  .sKdp,  602,  616 
Wrisberg,  cartilage,  274 

pars  intermedia,  465 
Wry-neck,  53 

Z. 

Zinn,  ligament,  347,  334 
zone,  385 
zonula,  385 
Zone  of  Zinn,  385 
Zonula  of  Zinn,  385 
Zygomatic  arch,  596 
fcssa,  693 

contents,  693 
fracture,  586 
Zygomaticus  major  m.,  636,  627 
action,  637 
insertion,  636 
nerve  supply,  637 
origin,  636 
minor  m.,  637,  627 
action,  637 
insertion,  637 
nerve  supply,  637 
origin,  637 


I 


^ 


1 


I 


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MNKD  OCT    ^1% 

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OCT  1 6  1979 


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